It's great that you're starting to think about this now! When I was 18 and went to college, I applied and got an American Airlines rewards credit card. I'm not sure if you need to be 18 to get your own card; however, having credit for a long time helps your credit score. I'm 29 now and my Trans Union score is 804. It would be higher but, believe it or not, I'm told I don't have a long enough credit history!
Suffice to say, I would also establish utility bills in your name (i.e. phone, cable, wireless, gas, electric). I believe this will help as well - just make sure to pay your bills on time.