For basics I would say just eat less, and get the calories you do eat from good sources such as whole grains instead of white, natural sugar (like fruits) over artificial sugar (candy bars), important essential fats like salmon and flaxseed oil instead of saturated fats and trans fats, etc.
There's this plan by david kirsch called the ultimate new york body plan which gets you about 10 lb or 2 dress sizes smaller in 2 weeks. It sounds crazy but the workout and diet are as crazy as what it claims. But it works, and for the most part its healthy. I know this because I did it. But you're going to have to follow it to the t for it to work.
He has another plan that I think is for over six weeks which seems perfect for your time schedule. I have never done that one but I am sure it yeilds about the same results in just a longer time.