Claudia, I had good luck on closets by simply emptying EVERYTHING out of it, cleaning and airing out the insides, and then reloading ONLY clothing and shoes that we have actually worn in the last year or so. I got rid of lots of stuff I really did like, but for whatever reason never wore. Now that my available wardrobe is of a manageable size, I am determined to replace only - if something new goes in, something old comes out. This works particularly well for garden clothes, which I tend to wear until they literally fall apart. I've also established a couple seasonal under-bed totes for clothing that is specific to summer and/or winter. I hope to keep it manageable.
My current bugaboo is my office supply closet. I used to run a business out of my home and have tons of stuff I really don't see any future need for, most purchased in bulk. Lots of file folders, copy paper, etc. along with baskets full of clips, rubber bands, labels, etc. The problem is keeping 10 file folders takes up about as much space as 50. I need to tackle that with a ruthless attitude!