Personally, I'm sort of opposed to the idea of people under 18 cutting a substantial amount. With that being said, the weight cutting thread was already linked, so...read it, know it, live it.
If you want more comprehensive advice, you should give a very specific description of yourself. Height, measurements, how much your weight usually fluctuates in a day, and current diet. Don't expect anything beyond "read the stickies" if you only ask "how can I lose X amount of weight in Y amount of time?"
Honestly though, even when you provide all that information, the answer is still "read the stickies."
Edit: by the way, you have a current diet. Your diet is what you eat, not "a diet." Give an example of what you eat in an average day.