Eat less, move more. About 5 years ago I went on Sugar Busters and lost 40+ lbs, which I've actually managed to keep off. The problem with diets are.. you can't stay on them forever. So.. watch your portions! When you sit down to a meal, leave some on your plate. Make a point to stop as soon as you start feeling full. And like mm mentioned, don't eat late at night! I have to snack at about 8:00, but I use a little bitty bowl for measurement, and eat nuts or cool whip. (I know.. that sounds nasty, but works)
If I can check cows without the four wheeler, I'll walk. When I get a new ranch listing, I almost always walk it. It's easy to get lazy and drive everywhere, but heck, with the price of fuel, it's cheaper to walk also!
It takes TIME, so be patient and don't waiver! Eventually it will get easier to eat less, and you'll find yourself shrinking in no time.