There are times I feel like I'm getting middle aged by EVE standards. I'm too young to have walked uphill in the snow both ways to work everyday, but too old for this newfangled Epic Mission Arc and Wormhole Space business. Still it gave me a chance to learn the hard way just how easy it can be to make yourself a half-way decent living in EVE just running missions in high-sec.
First of all, it's not hard as many new players think to get into a decent battle cruiser and get out there running level 3s. On the other hand, it's not as straightforward as the player about to buy their very first battle cruiser tends to think either. You'll need engineering, electronics and mechanic all to V. Targeting to at least four, long range targeting to at least four, drones to V and drone interfacing to IV. For the most part those skills aren't listed in the ship's prerequisites, but each of them is going to be vital to your survival on missions. And no matter how you tank, tactical shield and tactical armor manipulation are both needed to at least IV better V to make sure that your armor really protects that hull of yours, and the shield really works as a straight up buffer before your armor.
A passive shield tank will need shield upgrades IV, as well as all the shield compensation skills to IV, and active shield tank will need shield boosters IV. Armor needs hull upgrades IV, armor repair IV (quick note, don't even worry about armor repair V until you already have a cap stable ship, the decrease in cycle time will make it hit your cap harder as well) and armor compensation to 3, possibly 4 in case you want to fit an EANM.
Finally to get into the ship itself you really just need spaceship command IV, racial frigate IV, racial cruiser III, and then you'll want the battle cruiser skill itself up to IV. You'll also need whatever weapons your race favors up into the med IV range, as well as any gunnery, missile or drone bonuses you can pile on after wards.
I'm sure this all sounds like a lot, and even with a couple levels of cybernetics and friendly corp mates to get you into +3s this is going to take about 40+ days from a new character, though not taking into account the early training bonus. However, most of that time you'll be spending in a cruiser doing level 2s, or with a corp mate assisting them on missions. However, with these skills you'll become a self-sufficient isk producer, and begin to have brand new opportunities in the EVE landscape open for you.
I tend to think of certain ships as isk gates, and the battle cruiser is one of the big ones in high sec. So if you need something to aim for, it's probably your next big leap forward in the EVE universe.