You need to work out what you like eating and what kind of diet you can stick to. I personally favour Atkins, low carbing or the south beat diet (low GI) because I like eating meat and apart from pizza - which I havent had for ages - dont particarly like carbs that much. You can lose quite a lot of pounds in the first two weeks and 1-2 pounds a week after that, moreso if you exercise. Otherwise there are lots of other diets out there too like weight watches, eating subway low fat type options etc.
So what are your favourite foods would be the first question I would have to give you a diet.
Giving up bread, sugar, pasta and cereals can help you to lose a large amount of weight - I lost 20 pounds once in three weeks simply giving up these foods. Remember there is lots of Sugar in most processed foods so start reading the nutritional labels.
If you are into reading the below site is interesting. Basically no matter what weight loss method you choose, you need to lose 3500 calories to burn 1 pound of fat so by counting your calories you can ensure your weight is where you want it. http://www.hussman.org/fitness/
Remember how good exercise can be too. It doesnt have to be boring either, go out with friends and do something, play a team sport, or simply just relax and take a walk.
One last thing is with atkins or similar diets you enter what is called ketosis where you are burning your body fat and not using carbs to run. This can really help with weight loss and you can even buy sticks from the chemist to measure this called Ketostix.
I find it is really motivating to know i am losing body fat.