Make simple changes that add up. Exercise, of course. Take the stairs, walk further distances.

Switch out breads and starches for veggies. Eat a meat with spinach and tomato, instead of fries / pasta. Skip the soda, skip dressing and use more spices for flavor.

If you're gonna go for a gimmicky diet, I recommend the caveman diet: http://www.earth360.com/diet_paleodiet_balzer.html