Depending on your health and fitness goals, you'll need to commit to a minimum of 3 days of exercise each week to see results. Fewer than that and each workout will feel like you're starting over again.The ACSM recommends that healthy adults need to be performing a minimum of 150 minutes of moderate intensity cardio, 75 minutes of vigorous intensity, or a combination of moderate and vigorous intensity exercise per week. Resistance training/weight training should be practiced at least twice per week. Don't forget that you can break these recommended workout times into smaller chunks if necessary. Not having enough time to exercise is no longer an acceptable excuse ;)
Ideally, you should have some form of fuel in your system before you work out. Eating an easily digested carbohydrate an hour or so before you hit the gym ensures that you'll have enough energy in the tank to get through your program. Try fruit and yogurt or toast and peanut butter; not too much or you'll feel sluggish and heavy.
Excess fat on the belly, upper arms and inner thighs doesn't typically occur in isolation. If you've got it there, chances are you've got it everywhere. You can't spot reduce. No exercise will target fat cells in just one part of the body. You need to target them all via exercise and proper nutrition.And if you really want to see muscle definition once the layer of subcutaneous fat is shed, make sure you're following a strength training program designed for muscular hypertrophy (here's where having a personal trainer comes in handy).