Just starting to get your feet wet in EvE? Here's a brief list of things to do to keep the money rolling in while you find your feet and decide what it is you actually want to do...
Mining is the easiest and arguably most risk free way of making a basic income in EvE. It requires very little interaction on the player side and is a good way to make a steady amount of money while semi-afk.
The minerals gained from mining can be refined and sold for a further profit or used in manufacturing items, ships, ammo etc.
Mining has a very low level of entry but can be quite skill intensive if you want to reach maximum efficiency/ISK per hour. It is literally the first step in manufacturing, every item in EvE requires basic minerals to create, and mining is the primary source of minerals. This ensures a healthy, competitive market with the produce always being in demand.
More info: http://wiki.eveuniversity.org/Mining
- Mission running
Mission running is probably the most popular way of making money in High Security space. You will generally earn more ISK per hour running missions compared to mining, however running missions is more skill intensive, requires constant play/attention and comes with a much higher risk of losing your ship. Especially at the lower levels!
Running missions is a good way of making an income alongside levelling your combat skills if that is the area of EvE you are more interested in.
There are multiple sources of income from mission running. The main source of income from missions is NPC bounties and the overall mission reward awarded by the missions Agent. However you can also loot the ships you destory in a mission and further salvage the wrecks to make a bit more money per mission at the cost of taking more time to complete. This is far more lucrative once you reach level 4 missions where the NPCs will drop much better loot and provide higher quality salvage.
More info: http://wiki.eveuniversity.org/Missions
There are plenty more ways to make money in EvE, however missioning and mining are the least skill intensive and easiest to access from the moment you start the game. As with most things in EvE, the more people you take with you the more money you will make over time and the more risk involved, the better the rewards!