I know I'm several weeks late with this post, but you could still effectively organize and declutter your closet using this method. I can't remember where I originally heard about this. I tried it once or twice before, but I haven't done it every season because of being pregnant, busy, apathetic, etc. Here's what you do:
At the beginning of the season (ideally twice per year, once for spring/summer and once for fall/winter) take all of your hangers and turn them backwards in your closet like so:
Then go about your normal business getting dressed every day, washing clothes, and hanging them back in your closet. When it gets near the end of the season, you should notice a few (or maybe several) things that are still turned backwards. This makes it blatantly obvious what you are and are not wearing. By the end of the season, get rid of whatever is still turned backwards. If it's getting close to the end of the season and you just can't bear to part with something that is turned backwards, wear it. The rule is that you must get rid of it if you have not worn it. This is a really easy way to organize and get rid of stuff you don't need.