How to lose Weight this summer?

I'm 5 foot 8.5 inches, and I weigh 115 lbs. My thighs are flabby and I have some tummy rolls. I run on the cross country and track teams at my high school, but I'm still sorta fat. How can I lose weight but still get/stay strong for my sports?? I feel really fat you guys. Everybody tries to tell me I don't need to lose weight but I want to and nothing's gonna change that, I just need to know how.