I'm not terribly organized, but here is what I do: strips, all lengths, any width under 5", go in one container. Anything smaller than 2" goes in another. I cut 2" squares from other small pieces, and put those in a shoebox for a scrap quilt I'm slowly working on. All larger scraps are sorted into shoeboxes by color. There my system breaks down - I have a shoebox of random larger scraps not sorted by color, and anything a fat eighth or larger goes in with the yardage, stacked on shelves by color, except I have a lot of plastic bags laying around with all the scraps from particular projects together, or all the yardage I plan to use for a particular project. And all my old jeans and denim are in one box.
Umm, so that was more a description of my disorganization than my organization, I guess.