What can i do to lose weight?

I am 16, 5'10 and i weigh almost 200 lbs. As you know i am tall and i just want to lose some weight because i kinda sorta have a fat tummy. I threw the shotput and discus in Track and Field and now i am going to try out for volleyball. I try to eat right put sometimes i make bad choices.! So what can i do to help me in losing weight.??...Thank You