1. Hoard boxes of the same shape and size.
2. Label said boxes.
3. Include "catch-all" boxes with labels like "unsorted," "assorted," and "miscellaneous."
Here's the original mess, from my work on the Mosaic Angel:
Here are my organizing raw materials (plus some cardstock, not pictured)
Here's the final result:
This trick also works on a large scale, as you can see below. I have lots of fabric and misc. craft materials. (Yup, I save stuff 'just in case.' This also means that my husband is a saint.) It's not pretty, but I can find what I need.
If you are interested in trying to this trick, one type of uniform-sized box that would be easy to accumulate would be cereal boxes. Just cut off the tops at whatever height you need. Granted, they would not have lids, but depending on what you're storing and how, that isn't necessarily a problem.