Know What You Want to Accomplish
Do you want to get a new, high-powered job? Are you trying to meet the guy of your dreams?
Take out a notebook or journal and write down your goals -- in life and in fashion. Then start to think about which design elements and accessories can help you accomplish those goals. If you want to get a better job, think about adding a few pieces to your suit collection. If you're headed back to school, you'll want to trade in a few of the suits you already have for some casual knits and jeans.
Once you have your list in hand, take it with you when you shop. It can also help to bring along some pictures or descriptions of what you already have in your closet. Ask the salesperson to help you pick out pieces that will enhance your current wardrobe and help you accomplish your goals.