First off, don't rely on cardiovascular exercises too much. That means getting off the treadmill -- or stopping jogging -- soon after you feel warmed up. Jogging slowly over long distances or long periods of time won't really help you trim down quickly enough.
Instead of relying on long, slow cardio, mix up your workout regimen with some weightlifting and interval training exercises. Interval training is particularly important -- this is when you exert maximum effort into your exercise for short periods of time. A good example is sprinting, since you're probably used to jogging/running by now.
Strength training and interval training builds muscle and burns fat more quickly than long, slow cardio. If you compare the bodies of a sprinter and a marathon runner, you'll see that sprinters have more toned, sculpted bodies. This is a result of their intensive, maximum-effort exercises.