Im trying to lose weight, can you give me some tips?

ok well im trying to lose about 25lbs this summer. ive already started working out and eating less and stuff. but i was hoping someone would give me tips on how to lose more weight as i work out. someone suggested a plastic bag around my stomach while i jog but its not really helping me. I usually run for about an hour, come home and do 200-300 sit ups and jumping jacks. i am also kickboxing in my garage. i am 16, 5'7, and 145ish. can some one give me any tricks?