Go to the gym or have a lot of sex gym is a big one, or just more exercise in general. walking more instead of driving also helps. lots of small exercise can make a big difference. if you're fat and need to lose weight, changing your diet can go a long ways. don't use diet pills and stupid stuff, just eat less candy and ice cream and stuff like that and eat healthy meals. it's easy when you have a mom or dad that cooks for you, but when you don't... i guess you could do it yourself or avoid eating too much or too unhealthy foods when you go out to eat.