One of the easiest ways to get ISK in EVE Online is to Mine Asteroids. This methods may not be the most exciting or the most profitable, but almost everyone starts out this way to get their bank roll started. Once you get your feet wet in Mining you can upgrade your ship to hold more cargo and also invest some of your hard earned ISK and purchase some mining drones. These drones make the tedious task of Mining for ISK a little less boring. You can also venture out into a less secure area and mine, but it's a little more risky, as with a less secure area you are more prone to being attacked.
Lets talk about the upgrades for your ship for a second. If you determined that your job in your corporation is going to be the Mining Master, or you just want to make your ISK this way, then you need to learn the ins and outs of mining. You need to equip yourself with the biggest cargo ship that will also be able to handle itself in a battle. The players who mine for a living in ISK are the ones who pirates try to take advantage of. They prey on the big slow moving ships and usually hold them hostage.
One of the quickest ways to get yourself up to date on the best mining equipment and area's is to look at a EVE Online Mining Guide. I would also recommend searching the EVE Online Forums and ask around to learn some of the latest items from patches.