I'm sure you've noticed the different colored inserts in your stamp sets. The newer stamps actually label what catagory they belong to but the older ones do not. I have my stamps grouped by colors and have a running list in my head that makes sense to only me (don't ask, I promise, you DON'T wanna know). I recently came across a post on the CTMH consultant boards that lists what each color means.
Indian Corn Blue- Alphabets and Numbers
Lilac Mist- Frames/Tags/Borders/Backgrounds
Desert Sand- Winter
Crystal Blue- Everyday Life