The quickest way to lose weight, hmmm...
I woul recommend that you first analyze your current diet and eliminate any junk/unnecessary stuff. Like if you have sodas, or something similar...try to cut out at least 200 calories (roughly, don't go all psychotic calorie counting).
Next I suggest you take up strength training. You may not lose any actual weight from this but you will look leaner, feel better and be more healthy in the long run. Everyone should do it. For strength training basics just do 8-12 reps, 3-4 sets of pushups, situps/crunches, lunges and squats. Be sure that you are actually fatiguing yourself though. Lift enough weight so that you can only lift the weight 12ish times and then take a minute break between sets.
You should also supplement this with cardio. Do at least 30 mins (NOT including warm up and cool down -5-10 min each-) 3x a week. Do moderate activity. So speed walking, biking, running/jogging if you can do it, swimming...whatever. The more the better though so if you can do like an hour 5x a week...but start off with 30 mins 3x a week if you are just beginning.
The quickest way to lose weight and tone up and look great has always been to eat right, and exercise. Just doing one or the other has effects but both combined works best.
If you need more advice on diet my advice is always to base meals on vegetables, then whole grains, and then occasional lean meats. And be wary of sauces and stuff cuz they can add a lot of calories...
and drink lots of water...!
HTH