This is a trading guide. It offers you much higher income than any other EVE activity. However it does not involve shooting things (players, NPC pirates, asteroids) but transporting items between systems and updating market orders. If you hate these, don't read it. This is a rather long guide and you are not expected to read it at once. It won't go anywhere, you can return and continue.
Items in the game are generated by PvE activities: killing NPC pirates, running errands for NPC mission agents and mining. The people doing these want to sell their wares to players who want to use them. They are not in the same system, they are not online in the same time, they don't know each other and they want to sell/buy now. This is where you come into the picture. You set up buy orders in the places where the sellers are, move the items to the places where the buyers are and set up sell orders. The difference between the two orders minus fees is your profit. 10-50% profit isn't rare in EVE since most players are dumb and lazy or simply don't care.
What does a trader character do? Sets up buy and sell orders in one or more places. The skills he is focused to are the skills to be able to set up the orders and the skills and standings (reputation with NPC factions) needed to minimize the fees.
The first step in the way of building a trader (or rather any) character is to learn cybernetics. If you are a new player, lvl 1 is enough. This skill allows you to get implants that speed up your skillpoint collection. The +2 implants costs around 2M ISK, money you don't have as newbie. If it's not your first account and you are not a total newbie, I'd strongly suggest to learn Cybernetics 4 to be able to use +4 implants.
If you are a newbie who don't have money, you shall start your career agents because they will give you seed money. Start learning the Social skill instantly since it increases your standing (reputation with NPC faction) gain. Important: do the career agents for the faction you want to trade for. Each factions is friendly to one and hostile to two other factions. If you do missions (including career agent missions) to Caldaris, the Gallentes will hate you and you'll have extra fees in Dodixie. If you are not sure, start a Caldari first, as Jita is the main trading hub. So while learning the skill Social up to 4, you should do all 5 mission chains. Feel free to interrupt your training for a fast skill like Astrometrics needed for the exploring chain. You will get money for the missions and as soon as you get 2 million, instantly buy a +2 implant, you will find them by searching for " - beta", first buy the +Charisma, than the +willpower and so on. To finish the career agent missions you will need skills like Destroyers, so don't expect to finish them all in your first day. There is time. One important suggestion. In the scanning mission, get six documents from each container. You loot one, wait, it respawns, loot it again until you have 6.
If you are not a total newbie, and have money for a set of +4, then learn Cybernetics 4, get the set, then learn Destroyers 2, Faction Frigate 3, Targeting 1, Astronometrics 1, Industry 1, Hull upgrades 1, Afterburners 1, faction specific weapon 2, rapid fire 2, controlled bursts 2, Sharpshooter 2, Motion prediction 2. If you value playing time over skill learning time, train Caldari Frigate 3 and Small hybrid turrets 2 regardless of your faction. Small railguns with iron charge oneshots starter mission frigs from maximum targeting range, saving you lot of chasing. Get a cargo magnet to pick up the mission-loot they drop in that distance. If you don't have an L4 capable combat main, learn the Industrial skill from the same faction you learned Frigate 3. Get Anchoring 1. Remap for Cha 8, Will 6. Get Social 4, Negotiations 2 (or 3), Connections 3. Fit a destroyer and breeze trough the carreer missions. Don't forget to loot 3 documents from the exploration containers. Note: you will get the expert remap tip below.
Either way you have +2/4 implants, you have Social 4, negotiation 2/3, connections 3 and finished your career agents. Now if you are newbie, learn faction industrial ship 3. You received two primitive industrial ship from your career agents, you can replace it to better one by that skill. Get Anchoring 1 too to be able to use containers that increases your ship size. After these you shall also remap for Cha 8, will 6. You do it on the character screen, attributes menu, "remap now" button. 6 points to willpower, 8 to Charisma. The skills you'll learn will mostly use these attributes.
To get the easy standings, you shall complete the other two career agent bunch of your faction. Look up the linked WIKI page and travel to them in your destroyer. Each mission bunch provide another 10M money and good standings. If you are a newbie and didn't hate the missions much, you shall travel to the allied faction Career agents too (Caldari-Amarr, Gallente-Minmatar) are allies. When you have the money, replace the +2 implants to +3 for Charisma, Willpower and Memory.
You shall learn the following skills as a trader: Accounting 5, Broker relations 5, Contracting 3, Margin trading 4, Trade 4, Retail 5, Wholesale 4. Do not do them in that order. Elevate each to 1, then 2 (some can only be learned after other ones are high enough), then 3, 4, finally 5.
If you are not a newbie and you are 100% sure that your alt won't do anything else you can save about a week time by using all your remaps. Start with I10-P4 to learn Cybernetics 4, plug in the implants, learn all the various skills above, remap W10-C4 learn Trade 4, Retail 5, Broker 5, remap C10-M4. You can learn Social 4 on W10-C4 if in the hurry or in C10-M4 if not, EVE-offlining for 3 weeks before career missions. This is very much not advised to newbies who might want to manufacture, PI or seriously haul on this character and can't since they locked themselves to C10-M4 for 10 more months.
The mainstay of the standing increase is the storyline agents. You get a storyline mission after doing exactly 16 missions of the same kind, same level, same faction. You shall first figure out what corporation owns your hub. Jita is owned by Caldari Navy, let's use it as an example. If you have a main that can do L4 combat missions, you shall just fleet with your main, fly to the mission point in a capsule (NPC pirates ignore it) and let your main finish it. If you don't, you shall do L3 distribution missions in your industrial ship. If you go this way, you shall do them as fast as possible. Use the agent finder to find a system with 3-4 L3 distribution agent of your faction, pick them all up, complete them, return. If you are Caldari, I strongly recommend the Ono-chain. It is a series of systems near the system Ono. There is just one way, so the agents can't send you to different places. Complete exactly 15 missions. If you lose counting, you can open the wallet journal and filter for career agent rewards. After completing 15 missions (L3 distribution or L4 combat with main), go to a storyline agent of your target corporation. For Caldari Navy I used Nouteras Ashata. Fly to her base, open the agent finder and search for all agents of the same type as the previous 15. Find the nearest, and do his mission. Doing so will make the storyline agent sending you a mail in a few minutes. Then you can pick up the storyline mission which has superior rewards both in ISK/item and standings. You get lot of corporation standings and nice amount of faction standings. If you did L3 distributions, you can still get L3 combat storyline. Simply pay someone on the local channel to help you. Offer him 10-20M ISK and the loot of the combat.
Continue the above until you have 8+ standing before connections skill towards the corporation. The faction standing will be around 6. For now, that's tolerable and will provide around 0.35% broker fees. If you have a combat main, you can increase that significantly by doing the cosmos missions. If you have money to buy pirate tags, you can complete the datacenter missions. You can also do the Sisters of EVE Epic missions.
But let's not rush so fast. You are now in a mediocre faction industrial, like the Badger II. You can make OK-ish profit by buying up tritanium, pyerite and other materials scattered around the nearby regions and haul them to the hub for sale. Some regions are very close to a hub in another region. For example Jita is 2 jumps away from Lonetrek, The Citadel and Sinq Laison so you can haul from them to Jita. However such transports are strongly limited by the small cargohold of your ship and its weak tank. Industrial ships are slow and often scanned by pirates. If you carry more valuable cargo than N Tornado battlecruisers (71M), you can expect N/2 Tornados to attack you with 12000EHP oneshot. Get better tank, get cheaper cargo or forget the industrial
What's left for you in regional hauling: shinies! You can transport implants, skillbooks, pirate tags, modules and other small but expensive items in a small frigate sized ship like assault frigates, interceptors, covops ships. These can be learned in a week or two. You can set up regional orders changing the range of the order. Just watch out for lowsec systems, only covops ships shall go there for multi-million cargo. The NPC pirate hunters are selling their loot for your cheap buy orders and then you fly the items to the hub for sale.
If you have an Orca or Freighter, you can do the same for large volume, cheaper stuff like tritanium. There is a special market here: refining. You shall learn the skills Refining 5, refinery efficiency 4, Velspar/scordite/whatever processing 2 and you can buy cheap ores and haul them to the hub where you have high standings to process them perfectly to minerals like Tritanium, selling it.
Among the trading professions regional hauling has the highest return on investment, lowest risk (unless you do something idiotic) but lowest return on time. It's practically a grind where you transport for price differences. You can make good money even if you have just a hundred million seed money but you can't make more than 100-200M/hour even if you are very rich. It is the first trading profession I'd suggest to a newbie.
You can improve the ISK/hour by not hauling yourself but setting up courier contracts. You can set a public contract that anyone can complete or you can turn to hauling corps like Red Frog Freight or Push Industries. This way you give up some money but save all the hauling time.
The main problem of station trading is the 0.01 curse. If you set up a buy order for 100000000 and a sell for 120000000 you won't have to wait long until someone sets up a buy order for 100000000.01 and a sell for 199999999.99. The worst thing you can do is following the same strategy. It's for bots and people who consider time free. You shall cut the price agressively and should not camp the AH. Check prices twice a day maximum. In the the previous 100M/120M example you should go for 102M/118M then 104M/116M and so on, until the prices are within 2% which is near the profitability limit due to taxes and broker fees. The reason to do so is increasing volume. If the sell price is high, many buyers will say "screw you" and go farm it themselves or set up yet another 0.01 buy order. If the buy price is low, the farmers will say "screw you". If the two prices are reasonably close, they accept it and simply sell/buy so many items that all 0.01 orders before you are filled up and yours too. 0.01-ers usually leave at some point because they have to spend lot of time to update orders. 2M profit for 20 seconds is 360M/hour. The same profit for 1 hour camping is worse than mining veldspar in a frigate.
Station trading needs a few seconds per item so by adding more time you can add more items. Its return on time is better than regional hauling, up to 500M/hour if you have enough money. The return on investment is rarely more than 2-3%/day (remember not all orders fill up every day) which isn't bad but to cash in 500M/day you need to invest about 20B. The risk is that prices can drop overnight and then your sell orders don't complete, your buy orders do so you are sitting on items you bought for more than they are selling now. This case, unless you are very-very sure that it's just a temporary disturbance, you shall eat the loss and sell for this low price and carry on. If you wait, you can lose even more. Unfortunately in an unexpected price jump you get noting. Your sell orders complete on the old price, your buy orders not and you are sitting there without items to sell.
This is by far the most profitable activity, up to 1B/hour. However it needs the largest investment and holds the most risks. You must station trade the item in every single hub normally and on top of that you do the inter-hub hauling: if the item goes for 120/90 on Rens and 110/90 on Jita, you list it on Rens. Of course you can't list "too many" as Rens is a smaller market and they might not sell at all. Watch the price history tab. To do it right, you must know every items volume and price in every hub you work on. I would rather not suggest doing inter-hub hauling if you are new. On the top of the higher investment need, you need more alts (lot of time increasing stats) and they are sunk cost if you change your mind. The hub-hub routes also camped by pirates. They can't catch you if you don't fail, but one little mistake like answering the door can get your hauler to decloak on the gate and you lost your cargo.
My ISK posts can help you making EVE money. You can also join the "goblinworks" channel in EVE for market questions and discussions.