Green Lanterns advice is probably the best advice in this thread. Asking a bunch of people on line what they suggest might steer you in the right direction, but most people are going to tell you what works for them, which isn't necessarily what works for you.
The best place to start is a blanced diet and exercise routine, stick with it, then go from there. Don't get caught up in fad diets or routines, and most importantly don't take the advice of a 250lb plug in the gym when he asks if you want "real" supplements
