If you're so tired that you can barely stand up after an aerobics session, you're overdoing it. Not only will this decrease your motivation to keep up the aerobics training, it actually burns less fat in the long run. Your workout pace should be challenging but comfortable.

It can be hard to walk through the door of your aerobics classroom, but remember: everyone there has gone through the experience of attending that first class. Don't be embarrassed at your size or inexperience; as with everything, you'll get better with time.

An hour or two before heading out to your aerobics class, drink 2-3 cups of water to hydrate yourself, because you'll probably end up sweating a lot. Keep a supply of water close at hand while you're exercising, and take sips every 10-15 minutes.