How can i make my body better?

There's nothing you can do to change ANY of the things you hate about your body except for maybe losing inches off your waist. You're sixteen. You're not going to have a teenage girl's body forever. Maybe in a few years your breasts and legs will grow, or they may not. There's not much you can control about the way your chin looks or the size of your hands. You may just end up as a very petite woman, which is fine because plenty of guys out there dig it.