The things that work best for me are:
Not actually going on a diet, because you just think of food and how hungry you are all the time.
Don't eat because it is "mealtime" i.e. breakfast, lunch, dinner. Eat only when you are
actually hungry. There are a lot of myths that eating constantly makes you lose weight, it's not true for most people, because you are taking in so many extra calories!
Sign up for a gym that has group classes, they are FUN, and if you don't go you'll feel bad that the money is coming out of your account even if you don't go! Building muscle will help you more than anything because it raises your basal metabolic rate. This means you burn more calories just doing day to day things the more muscle you have.
I find I get into phases where I'm eating too much (like staying with my mother) for a period of time and can no longer tell when I am truly hungry/full. Not eating for 1/2 day seems to "reset" this mechanism and you can definitely tell the difference between really feeling hungry/full and thinking you might be.
Get enough sleep! At least 8 hours!
Eat slow, it can take 20 minutes for your body to respond to the food being in your stomach.
Drink enough water, it sounds strange, but is very easy to confuse thirst with hunger. Drink before and while you are eating, you fill up faster and it slows down your eating.
Don't make any foods "off limits" it will only make you want them more, gorge on them when you break, and make you unhappy! Instead, just limit yourself to one bite!
Use SMALL plates and bowls, it really makes a difference in the amount of food you get out for yourself.
Generally, a fist size amount of food should be enough for a meal (unless it is something like salad).
Use fitday.com. It is free. You can track everything you eat and the calories and nutrients you are taking in, your exercise, your measurements, etc. It's very rewarding to see how you've changed over a few months if you stick with it.
If you can't control what you eat, stock up on LeanCuisine, they are healthy and taste great, and are the appropriate amount of calories. Just have to make sure you don't ruin it by eating a bowl of ice cream right after!
Good luck to everyone