Whats a good way to lose weight?

im weigh 142 last time i checked n im like 5'3ish or a bit shorter. i noe i weigh alot but ppl say i dont look like i weigh tat much. i do sports n i work out alot. my fat is on my tummy n my legs. my legs arent huge even thou i think so tey have more muscle on tem thou. the biggest problem is my tummi how can i lose weight ther? n any diet tips would help. Idono if i weigh tat much b/c of my muscle or w.e. in cl be4 the summer we had our bmi checked my teacher said i was fine but idono...help plezz im young soo no like weight losin pills i perfer losin weight with my own hard work ;D thx