This is probably going to be the first of two posts about organization, because organizing your stash in a way that will encourage you to use it is slightly different, to my mind anyway, than organizing it for more long-term storage.
This kind of organization is meant to be inspirational, so that you’ll see different yarns together and just want to grab them and start working with them. It’s the kind of organization that gets those balls out of your stash and onto your needles.
Exactly how you go about organizing your stash for use will depend a bit on what and how much you have, what you’re planning to make with it — if you have any ideas so far — and your knitting style. 
For instance I’m working on a giant blanket so I have a big bag full of little odd balls (and some larger balls that I don’t think I’ll use for other projects) so I can just grab that or pull out a couple of balls at random when I want to work on the project.
Some of my stash is organized by color, so I might be inspired to put two fibers with different texture but a similar color together (I’m working on a light blue scarf that’s alternating mohair and a ribbon yarn right now; I’ll show you more when it’s done). Some of my stash is arranged by fiber — all my cotton yarn is together, and all my Cascade 220 — or weight (sock yarn) so if I want to work on a project using those kinds of yarns its easy to find what I need.
You might have a couple of projects in mind already just from looking through your yarn (if you don’t, most of the next couple of weeks will be devoted to giving you ideas) so you should set those yarns aside. Put them in a pretty basket or bowl somewhere you’ll see them often. Hear them calling to you.
Or just make a basket or bowl full of a bunch of yarns you like. They don’t have to “go together” or make any sense other than the fact that you like them. Spend some time looking at them and thinking about them.
And get ready to knit.
Have you started (or finished?) any projects from your stash lately? I’d love to hear what you’ve been working on. After that scarf, I’m thinking hard about a multicolored linen stitch bag.
I have just learned to knit but I hsve been crocheting for years. I was wondering if there is a pattern that uses both crocheting and knitting. It would use up ny stssh faster too.
I am using my stash on scarves to donate to a local homeless shelter.
My stash is organized by type (dish cloth cotton, sock, etc), then grouped by color family (warm, cool, neutral). That works best for comparing color combinations for me. I’ve been knitting stuffed hearts for a Valentine display and for gifts, in between knitting a sweater for my dog.
Mines a mess but I like KateMet idea.