I love this! I've gotten to a good (minimalist) place with my clothes, as I've gone through my wardrobe probably 5x in the last two years, ruthlessly culling, and I so appreciate this challenge.
Something I found really helpful, was to think about how the clothes fit into my life ...as it is. So, if a piece of clothing is perfectly nice and in good shape but I don't wear it because for some reason the cut isn't totally comfortable? Get rid of it. If it's a nice piece of clothing, but I don't find occasions to wear it, or wear a different (skirt/dress/pants) as my go-to? Get rid of it. Basically, doesn't matter why, even if the reason isn't logical, if I just don't.wear.it. - why keep it? I definitely knew which clothes I hadn't worn in the last 6 months, but you can also do this looking forward, as well. Just turn all your hangers in one direction, then anything you hang up later (after wearing), you turn the hanger the other way. This way, at the end of the season (when you would reasonably expect to have worn the clothes during), donate everything that you haven't worn. I have gotten rid of a ton of clothing so far, and there's only one piece I regret (as in, if I saw it today, I would re-buy it).
I also culled items I had many of, and things that weren't stylish or well-fitting. For me, I had a ton of big & comfy sweaters that were pretty damn unflattering (and some similar sweatpants). Now, I know myself, so I didn't get rid of everything because I like to be comfy and don't really give a damn what others think, but I also wanted to remove the temptation to dress like a slob always, and make it easier to be comfy AND well dressed. And it's working well.