What should I do?

I'm a 16 year old sophomore. I'm 6'2 with dark brown hair, greenish/grayish eyes, and a muscularish (working on it) build. I've tried so many ways to get a girlfriend. Now, to be fair, the way I made these attempts last year, in retrospect, was quite stupid and doomed to failure, especially since I was a new student and nobody knew me. How can I attract a girl who I can date?