The biggest tip offered is to reorganize your closet and drawers. When you pull everything out you'll be amazed at what you forgot you had! Think of it as therapeutic inventory...
Try on pieces you haven't worn in a while. It maybe at the moment you put it on you realize with a little tweaking (say wearing a newer blazer with an older forgotten dress) adds a whole new life to the outfit. The style editor also recommends going all out and pairing the clothes with shoes and accessories while you're at it. Then snap a picture to remind yourself that it's there!
Put unexpected pairings together. This is a tried an true method that store display people use often. A sweater or blouse you've always paired with jeans might be amazing over a black dress or a flared skirt!?
Have fun...Outside of gift clothing everything you have you must have loved once. Odds are they have a reason for being kept in the first place. If at the end of this you are still not happy with them you'll at least know for sure and your remaining clothes will be given new life.