In terms of diet, you want to make sure to get enough protein at every meal in order to keep positive nitrogen balance and keep your muscles growing. Focus on getting at least 1 gram per pound of body weight and make sure your protein is coming from quality, lean sources like fish, eggs, chicken breast, lean steak and whey protein powder.
You also want to make sure to eliminate all of the empty calories from your diet (soft drinks, junk food, processed foods, etc). Focus on eating whole foods and stick with good fibrous carbs like broccoli, squash, green beans, mushrooms and zucchini. Your starchy carbs should come from whole wheat sources like 100% whole wheat breads, brown rice and whole wheat pasta. Stay away from white flour as much as possible.
In terms of cardio exercises, you want to focus on doing the correct movements at the right intensity to force your body to burn fat all day long. This really comes down to using high intensity workouts to really start burning it off. I would highly recommend jumping rope for your cardio. This is by far one of the best overall body workouts to burn major calories and keep your metabolism stoked throughout the day. Your high intensity cardio session should never last longer than 20 minutes and focus on starting off with 5-10 minute session when starting out. You want to work at about a 85-90% intensity level and go for 1 minute straight. Then, take 1 full minute rest and start again for 1 minute. Do this for the next 5-10 minutes and you will be ready to get out of the gym! The great thing about jumping rope is that it also is an amazing exercise for your inner-outer thighs and your butt.