Wear clothes that are becoming, no matter what size you are. Choose colors that compliment you and features that hide flaws and highlight assets. Don't stuff yourself into too small clothes. As you lose, chose more fitted clothes that will help you gauge your progress and motivate you to keep the weight and inches off. At some point, a belt will become an accessory!
Looking "well put together" improves your career opportunities and will boost your self image. Gradually move from drawstrings to zippers.