Do it with something I like to call Interval (or variable, one of them) Dieting. You lose a certain amount of weight in a certain amount of time. For example, 30 pounds may sound like a lot to you. How does 10 pounds sound? What about 5? With my diet, you lose an easy amount of pounds in an easy amount of time. You might decide to lose 5-10 pounds each month, thus losing that weight in 3 months.
If you'd like to lose and keep the weight off, most importantly, DO NOT DIET!!!!! If you want to lose 30 pounds for a temporary period of time and aren't concerned about the negative health ramifications, by all means, knock yourself out!!!!