The following strategy guides have been taken from the star traders RPG forums and wiki, and are intended as a general strategy guide. Remember to always follow your captain's instincts!

Merchant

Rumour-based Trading

Rumour-based trading is the most profitable activity for a Merchant. For this reason, you must make gathering Rumours one of your top priorities. Your Charisma is already very high. Charisma is a key factor in Rumour availability, so once you have other skills and attributes up to acceptable levels, increase Charisma to improve your Rumour edge even more. Be sure to stop in every world and check for Rumours. It's worth making detours and going off the beaten path just to get more Rumours. If you stick to only a few worlds, you will exhaust the Rumour supply. Remember to look at both the Palace and Spice Hall Rumours whenever you can. It makes sense to Buy the rumours whenever you have sufficient cash for trading. The reason is that if you use only free Rumours, you have a chance of missing some 'concrete' rumours and getting 'flavour text' instead (tips on rules or aspects of story). Whereas if you Buy rumours, you are guaranteed to get the maximum possible number of 'concrete' rumours - specific, actionable events at specific places. Buying a rumour is simply an offer to buy a rumour, if it is concrete. Flavour text rumours are still free.

Pay attention to the Spice Hall and Palace ratings which affect the quantity and quality of Rumours available. Remember the good locations and be sure to visit them regularly - allowing time for the supply of Rumours to regenerate. Also consider selling Records (and Spice?) into the Market, prior to checking for Rumours, as this can increase the amount of information. Also, be sure to move around the Galaxy, as most rumours are localised. If you stay in one spot, you will miss valuable Rumours from other parts of the Galaxy.

Equally, before reacting to a Rumour, consider the location. If it is extremely far away, particularly if it is in a hostile area or Red zone, with few worlds where you can resupply and recover, you may want to leave that Rumour until you are stronger.

Useful Rumour Types

The kind of Rumours that are concrete and actionable for a Merchant are:

Positive Rumours - Create Opportunities
Shortage - far and away the most profitable Rumour, but also the most time-urgent. Drop everything, head over there, buying any stock you can get along the way, at anything short of ridiculous prices.
Surplus - still a very valuable opportunity. Sell or cache your cargo and head over. The time pressure in Surplus is to buy, not sell: you can sell later, at your leisure, but hurry to buy up all you can, while prices remain low.
Surge in Trading - opportunity to buy large quantities at 'flat', low margin, close-to-average prices. An excellent counterpoint to a Shortage. This also an excellent time to buy influence with the Factions. As the buy and sell prices are so close, the normal losses that you make when trading in Contraband and Records, to curry favour with the Factions, are significantly reduced.
(others?)
Mixed Rumours - Create Both Problems and Opportunities
(Single World) Trade Embargo - an opportunity to create Trade Records
Trade Ban - an opportunity to create Trade Records by selling the banned resource
Tax - an opportunity to create Trade Records by selling the banned resource
Refugees - (does this actually affect prices, even if occurs at or very near to an Urban Zone?)
(others?)
Negative Rumours - Avoid These Sectors
Exchange Closed
(others?)
Null Rumours - Do Not Impact Trade, Despite the Wording
Spice Traders - Increases the number of Rounds of Spice available in the Spice Hall, not in the Exchange.
Resource Rush - The increased availiblity of natural resources in a Wilderness Zone does not seem to have any effect on prices or quantities in any nearby Exchange. (Verify)
Dark Age Technology - The increased availiblity of Alien technology in a Wilderness Zone does not appear to have any economic effect. (Verify)

Galactic Events

Galactic Conflict Events can have a major impact on trading.

The most significant is the Faction Trade Embargo. Each such event means there are 2 Factions - around 10 worlds - where you cannot buy or sell without a Reputation penalty with the other faction. You will need to think and plan carefully before trading on these worlds, making sure it is justified. You will also need to reconsider how you exploit trade opportunities and trade routes without falling foul of the Faction Embargo.

It is often the case in the game that there are multiple Faction Trade Embargoes in effect. This can making trading very difficult. You may need to trade mostly between Independent worlds until the diplomats are able to bring some of the Embargoes to an end.

How best to deal with each kind of Galactic Event as a Merchant:

Note that the Trade Alliance and Spy Battle events only gain you Reputation, not profit. But, assuming that you actually want these Reputation gains, you can obtain them more cheaply during these events. So you don't make profit, but you do save money.

Normal Trading

Normal trading - meaning trading when no Shortage, Surplus, or other special economic condition is present - is what marks out the true, skilled Merchant from the mere profiteer. It is a difficult path, and success comes slowly, from persistence, discipline, caution, preparation, analysis, planning and carefully calculated risks.

General Tips for Normal Trading

Stockpiling

The Arguements Against Stockpiling

Stockpiling as a general approach is not recommended for a Merchant. Time, after all, is money. The best course of action is almost always to sell as soon as possible for a reasonable profit, rather than waiting some indeterminate period of time for a possible higher profit - that might never materialise.

Consider the classic situation where Stockpiling is usually recommended: During a Surplus, a captain buys a shipload of widgets for $1000, vs the normal price of $5000. He caches the widgets in a Wild Cache, or in Drydock, or (coming soon) in a Warehouse or Player Base. A year later, there is a Widget Shortage elsewhere in the Galaxy. The captain goes to his stockpile, gets a shipload of widgets, and sells them into the shortage for $25,000. Net profit: $24,000.

Now consider an alternative approach. The captain buys the shipload of widgets for $1000 and sells them more or less immediately for $5000. A year later, the shortage comes along. This time, rather than travelling to his stockpile, he travels to any world with a reasonable price and quantity of widgets. He buys a regular-priced shipload for $5000 and then sells it to the shortage world for $25,000. Net profit is the same: $24,000.

The key difference between the two approaches is this: in the first example, the Captain's first $5000 profit is locked up in the stockpile for a year. In the second approach, the $5000 is available during the year to make more money. Keep in mind, you are a Merchant and trading is your main activity. Trading always requires working capital. If you can't turn that $5000 into at least another $10,000 in a year, through purely normal trading, perhaps you should consider a different career!

This is the most extreme example, of surplus-into-shortage selling. However the same argument applies equally to normal trading, if not more so. Any time goods are in a stockpile, that is your working capital not working to make you money. Better to sell for a 10% profit today, and reinvest in another trade, than to sit for weeks or months earning a big fat zero % all the while.

And in fact, since all forms of stockpiling carry risks and/or costs, the return on stockpiled goods is actually worse than zero %.

The Arguements for Stockpiling

There are circumstances when stockpiling, at least temporarily, can be a good idea.

If there is a surplus, it can be good to buy up the entire surplus first, stockpile it, then (immediately) sell it. The reason is that if the quantity available is many multiples of your cargo capacity, you may only be able to make a few trade runs before the surplus ends. Any of the low-priced resources that you didn't buy, is then wasted (lost) profit.

Conversely, if your cargo capacity is many times higher than the typical quantity available (i.e. you have a very big ship), you might want to stockpile ahead of time, to make sure that you can collect a full shipload quickly whenever a shortage appears. This is not likely to be the case for starting out Captains.

Also, if political or economic conditions are currently very unfavourable - war, piracy, aggressive police actions, widespread Faction Embargoes - you might want to stockpile until conditions are more favourable for transporting and selling.

Special considerations apply to stockpiling of trade items that affect reputation - Contraband (Weapons, Electronics, Artifacts) and Records. Carrying these cargoes can be dangerous and it may be important to stockpile until the time is right for a well-planned contraband run. Sale of these goods can be done for political reasons as well as purely financial reasons. Therefore you might want to keep a reserve of Reputation-influencing goods, in case you get into a difficult political situation with one or more Factions and need to buy back some favour.

Records trading

Records trading is a relatively safe way of improving Reputation. It will not make you a profit, outside of Shortage / Surplus situations. Like Contraband trading (see below), it is a way of buying influence (Reputation) for cash. However there is profit to be made by selling the special Economic Records that Merchants (and Smugglers) can generate for themselves simply by Selling any resource (apart from Records), due to their "Economic Records" special ability. These Records are effectively free, and so can be traded profitably even under normal (non-Shortage/Surplus) conditions.

The special Economic Records tend to be created in compensation for a sale that was not particularly profitable. However this game mechanic is very new at the time of writing and not fully understood, so no more specific advice or information can be given here.

Contraband trading

Contraband items have the highest buy/sell prices in the game. This means they potentially have the highest absolute profit per ton (cargo unit) and potentially the highest profit per shipload / per trip. In addition, trading in contraband items gives Reputation bonuses (though often also gives Rep penalties).

On the down side, Contraband trading, outside of Shortage and Surplus conditions, is never profitable. The buy vs sell spread is too high for normal trading to be profitable. In normal situations, Contraband trading is simply a way of turning cash losses into Reputation bonuses - in effect, you are "buying" Reputation with your (lost) cash. And of course, dealing in Contraband exposes you to Reputation risk and physical risk from Faction warships and privateers. To protect yourself from this you need to manage sufficient Reputation and good behaviour to maintain Trade Permits with all Factions - all of which is costly and detracts from profit. Even when protected from Faction warships and privateers, you are still exposed to attack by Independent pirates (but would they attack anyway even with non-Contraband cargo?).

My suggestion is that Contraband trading is only worthwhile when there is an active Shortage or Surplus. For any necessary work on building Reputation with Factions, trading in Records is much less risky and more suited to the Merchant. Having said that, it is very advantageous to maintain as many Trade Permits as possible so as to be able to take advantage of Contraband Surpluses and Shortages when they arise.

Working Capital

The previous point about Contraband Shortages leads to a recommendation on working capital. You should maintain enough working capital to fill your hold with the most expensive Contraband item (Artifacts), at normal prices, to respond to a Shortage. This means you need around $3000 per ton (unit) of cargo capacity. E.g. with a ship that can carry 50 tons, keep $150,000 on hand.

Don't be tempted to spend this money on Upgrades or other luxuries. Working capital is capital, you invest it, you don't spend it. If you have more than $150,000, that's money in hand, you can spend the excess. But don't dip below the $3000/ton, except of course if you are investing in saleable cargo. Even then, keep in mind that you might have to sell that cargo at a bad price, or cache it in a hurry, to exploit a Contraband Shortage. So ideally you would $3000/ton in hand in cash, even after the investment in your current cargo.

Of course at a lot of stages in the game, you don't have this much money on hand. The point is that you should be very, very frugal with your money until your cash reserves exceed this level. Once you are above this level you can start spending on upgrades or, better, saving up for a bigger ship with a bigger hold.

Even if you never intend to trade in Contraband (never say never), the same principle applies. Keep between $600 and $1000 in cash on hand, per ton of cargo capacity.

General Tips for Merchants

Non-trading activities

Star Traders RPG is open ended and Captains are quintessentially resourceful. Therefore from time to time, a Merchant Captain will stray into other activities and other ways of making a living. Keep in mind that dabbling in these activities is one thing, but investing in them - by allocating skill points, ship upgrades, Reputation loss, hard-earned money and, most of all, your precious time - you are detracting from your growth in stature and capability as a Merchant. That said, there are a number of possibilities, and some of them are almost unavoidable, at least at certain times or in certain situations.

Contracts / Missions

As a starting Merchant, unless you are very strict purist, you will use Contracts to build up your initial working capital, reputation (for Permits), and money for any essential upgrades. Building up a viable trading career without using Contracts (e.g., following the "Iron Code" of the Merchant) is very challenging.

As a Merchant, it is preferable to stick to the easier transport Contracts. Secure datapad message contracts have lowest risk (zero, in fact, apart from the risk of failing to complete them). Cargo and passenger contracts have a risk of loss of Reputation and permits. If you take these contracts, it is best to only take those against independents (and ply your crew with Spice accordingly to compensate for their disquiet).

Surveillance and Blockades

Previously, it was sometimes useful to undertake freelance Surveillance to generate Records. However, now that Merchants have the ability to generate Economic Records through trading, there is very little reason to do this.

Both Surveillance and Blockades invite a high risk of confrontation with military warships that are defending their sovereign space. Surveillance, Blockade, and of course, Bounty Hunter contracts depend on skills and ship strengths that a Merchant does not have nor wish to invest in developing. As the Merchant is not well suited to combat, these activities are best avoided whenever possible. These types of missions are also time consuming with a high risk of failure that is difficult for a Merchant to control.

In turn, this means the Merchant should generally prefer Spice Hall and Palace contracts to Military Base contracts.

Combat

Combat should almost always be avoided by the Merchant except in unavoidable self defence. Flee if possible. Surrender is (almost) always better than death. You should outfit your ship for evasion and escape. This means avoiding upgrades that give a penalty to avoiding encounters, increasing your Stealth, having high Sails, and (for orbit escapes) high Engines (for escape when in Orbit, when Sails are furled). High Sails also benefits your trading profits by reducing fuel consumption and improving fuel prices (by expanding the range of planets you can refuel at). As a secondary priority, increase Pilot and Tactics to aid with escaping from a battle. Torpedoes are the best weapons to fit to your ship, rather than guns, as you will be trying to fight at long range while trying to escape. The Aft Torpedo upgrade could be useful, as it aids with escapes.

Military Rank

Military Rank is an expensive thing to pursue (particularly in terms of Reputation) and has limited benefits for a Merchant. The primary benefit is in increased Contract payments, and Contracts are not your main activity - certainly not once you get established. Getting just a basic military rank (level 1) with your home Faction (and perhaps some other Factions) is useful for making Star Dock Military Base upgrades available - including many non-combat upgrades such as Cargo Pods. Beyond this a certain level of Rank (maximum of 5?) can be helpful in avoiding Warship encounters, but then since you're not doing anything illegal anyway (right?), you don't need to spend that vast sum of money on dodging the legitimate authorities, do you?

Bounty Hunting

Don't waste your money on expensive Faction Death Warrants. You will not be doing any bounty hunting, or not enough to justify the cost. Buying the Warrant will just tempt you. A Death Warrant also confers the benefit of not being targeted by bounty hunters of that faction (is that correct?). But again, don't be tempted to buy this 'insurance'. Instead, you should just keep your Reputation from falling too low. Keep on at least commercial good terms with all Factions and you won't ever need any Death Warrants.

Smuggling

Some say the line between the Merchant and the Smuggler is a blurred one. Much like the Pirate vs the Privateer, the exact same activity can be viewed as honest commerce by one Faction, but by another Faction as Smuggling. If a Captain chooses to trade in Contraband or Records, unless he or she obtains and at all times maintains a full set of Trade Permits with every Faction, she is arguably a Smuggler at least to those Factions that have not licensed the Captain to carry restricted goods. Any Captain who takes a mission to deliver a secret cargo, or passengers who are keeping a 'low profile', is in the territory of the Smuggler.

The hard and fast rule is that if an activity will cause offence to any Faction (if they detect it), then it is probably some form of Smuggling. Even breaking an Embargo falls somewhere into the orbit of the Smuggler. The Factions blur the boundaries further by licensing their Privateers to prey on any Merchant who has not stumped up the cash for that Faction's Trade Permit, regardless of whether the Captain carries any Contraband cargo.

Since almost every Captain will at some time or other be tempted, for the sound goal of making a profit, to stray outside some or other Faction's self-serving definition of legality, remember the advice of Smugglers from time immemorial: just don't get caught.

Piracy

Of all the things that a Merchant should strive to avoid in his or her career, the paramount two are acts of violence and acts of illegality. While the Smuggler and the Military Officer partake of one of these vices, the Pirate's nourishment is a heady cocktail of both. Some say a Pirate is just a Merchant with a knack for getting an excellent Buy price. Don't be fooled by such sophistry. The Princes and the Clans hardly need one reason to take your cargo, seize your ship, and make your body dance to the tune of a boarding-laser - so don't give them two reasons.

Exploring

Ah yes, Exploring...

The life of a Merchant is a hard one, buying low and selling high, living off nothing but the sometimes razor-thin margin between the two. How tempting is it then, to consider that instead of buying your trade goods at a hard-bargained price in the marketplace, with your precious hard-earned credits, you could simply harvest them from the ground, or collect them from some long abandoned ruins? It does not take the fiendish number-crunching skills of a Bellixian actuary to figure your profit margin in that case - a cool, crisp one hundred percent profit. What Merchant could resist that temptation?

And yet, resist it he should.

The principal reason is the same as the reason to avoid dabbling in the activities of any other class of character: In order to have any success at Exploring, you will need to focus time, effort and precious cash to acquire the necessary capability. You need to spend your training time on skills that you otherwise have little need for, at the expense of your core skills as a Merchant. The true Explorer has little need of Negotiation skills, as he gets his sale goods for free, and every credit he receives is pure profit. Whereas the Merchant feasts or starves according to his success at negotiation on the Exchange.

And the same is true of the Merchant's ship, as for his person. Rather than optimising her for trade and commerce, she will heave at the bulkheads with noisy, good for nothing ground-crew, useless hands consuming valuable water-fuel. You will be tempted to purchase exotic upgrades for atmospheric operations, at the expense of profit-making cargo space, or prudent defensive measures.

There are other "opportunity costs" beside these. Even if you can stomach the immorality of using your crew as just another free, expendable resource, the distraction and disruption of frequent recruiting tours to replace the men you have sent to their death eats in to valuable trading time. As does every scouting voyage you must make to find new Zones to exploit, when Zones run dry as they inevitably do. Every hour in space headed toward a Wild Zone, or a rumour concering a Wild Zone, is an hour not spent seeking out the best trade routes and milking those trade routes for every loose credit.

If these arguments do not convince you to keep your vector tight, if you still feel tempted to stray from the path of the pure Merchant, then let me commend to you The Tale of the Merchant Brothers. A most cautionary tale.