First of all, you are going to have to do just three things. You always have to keep them in mind, and I would advise you to make them even as your habit, because it would lead you to have a permanent body figure after succeeding with your diet.
1. Drink a lot of water.
Personally, I carried around water bottle everywhere, and filled them up every time it was empty, and I consciously drank 2 liters of water a day. At school, at work, at home. This sounds very easy, but you will have to go to the bathroom a lot more than normal. The reason why this works is that it flushes out all the remnants in your stomach that had not been cleaned for years. That helps you get faster metabolism, and after the remnants had been washed off, whatever you eat would come out every quickly. For me, it worked after about 5 days. But i kept on with it for about 3 weeks just to make sure. But then it became a habit, I still do it, and I have not gained any more weight since then.
2. Do not eat after 8.
Everything you eat after 8 goes straight to your abdomen and other areas that would make you look ugly. That is because your metabolism is slower at night, and it stresses your intestines. It is not only bad for your health, but you will gain weight in the most awkward areas.
3. Have 6 meals a day.
It is better to spread your meals out, say, 6 small meals a day, rather than 2 big meals. So try to eat a lot, but small portions. It would help improve your metabolism in a long run.
These three points are the every-day plans that you have to follow and make them as your habits. Otherwise any kind of most effective diet plans will not work.