Start your IRA, or 401k early. Don't wait until your 40s. Life is short. Go out and find a job that you like. At your age you can try all sorts of different jobs and have nothing to lose. You won't really be able to do that once you have a wife and kids with a house to support.

Don't run out and get a bunch of credit cards to charge a bunch of stuff on it. My buddy in college took out an extra loan in college. He bought a TV and a bunch of other electronics. Between him and his wife they had over 30k in debt. The house that they fixed and flipped had all the profits go towards their debt.