There's not much you can do except try Rogaine or Propecia. Neither drug, however, is likely to help a receding hair line.
I started losing my hair when I was in high school. I'm in my twenties now, got a nice receding hair line, and fine, thin hair on top. I'll probably be bald by age 30.
The best advice I can give you is to embrace it. Propecia is expensive, could have some undesirable side effects, and probably won't help you much to grow hair (however it will probably do a good job at maintaining the hair you've got). Rogaine, in my opinion, just isn't even worth the hassle.
I've basically conceded to the fact that I'll be bald, and I'm starting to come to grips with it. If you just let it go, you'll eventually except it. Try working on things you can control and not things that are fated by genetics. Work on your physique, wardrobe, etc.
Anyway, if you must have hair, talk to Tom Brady. Every year he seems to have a little more hair than before.