1. You're still young. Women that age (and yourself) are still developing all the connections in their brain that handle logical thinking. It happens with everyone up to about the age of 24. Ergo, they go after the strong emotional relationships and wonder later why they got hurt instead of staying in the steady relationship with "the great guy"

2. Do your thing and be a gentleman. Again, you're still young so do what it is you do; basketball, working on cars, college studies, whatever. Instead of looking for a relationship actively, as Frankbtl said, work on you. Do the things you enjoy and go down your own path. When you find a girl on that same path, then you'll know she's for you.