Move most of your clothes (try it first with tops) to a closet in another room. When you need something to wear, grab it from the other closet. Once it has been worn, it can be washed and put back in your original closet. Anything left in the spare closet after 3 months, donate!
You can do this a few times a year with the different seasons. You can do it with pants too though I know most of us have more of a surplus in the tops department. If you haven't worn a certain tank top all summer long, are you really going to miss it when it's finally gone?