Can you please tell me which is the top crash diet, and how do i do it?

There is no such thi: If you are serious about controlling weight, you need to read up about energy balance. You need to develop a life long discipline to create a balance of energy(calories) taken in(as food) and calories burned(with physical activity). If you eat less and exercise more, you can lose the extra weight but there is no quick fix...You just have to change your behavior for the long term.