Hoooooo boy. This is the tough topic for me. In many ways, I'm very organized and in many more I can't begin to claim mastery over my stash.
A number of ideas leap forward:
-I tend to buy stash in bunches, with long spaces in between. For instance, my last buy was on my birthday last month. Had a wonderful time, and didn't plan on buying anything except the green yarn for "Pretty Thing". My prior buy was a Knit Picks order for yarn to make a Tam and Kilt Hose for a match to a Wallace Tartan kilt. Before that, a couple fleeces from my favorite shepherd (one of them was a 13 pounder from a Corriedale ram named Jake, the other was a pale silvery blue-gray from a sheep named Sierra, whose fleece I'd bought the year before). As I look at it, and think about it some, the sequence seems to repeat itself. I'll buy fleece for a while, then some rovings or top in fun colorways, then yarn. I love to spin and knit, but I tend to do a little of each, rather than long marathon runs of either one. Hmmm, hadn't thought of that before.
-My stash includes yarn, of course, as well as roving, top and fleeces in various stages of processing. If you've been following this blog, you've read about my adventures with the Nasty Romney fleece. It is, at last, all washed and dyed. Some left white, just for fun, but I've been picking and starting to spin the stuff. I can't say that it has been purely wonderful to work with, but I am finding that I enjoy the silky nature of the Romney. It really wasn't what I had expected, and that is part of the fun of spinning.
-I do tend to work through a fleece, start to finish. Rather like I've been blogging about with the Nasty Romney and Dolly Dorset in earlier posts. Instead of leaping from one fleece to another, I notice that I try out a lot of ideas with the fleeces I'm working with at the moment. I do a lot of swatching and small batches and I really enjoy the process. This way, I get to find out what I like about the fiber. Like the Louet Northern Lights top in Wild Berry Jam. Spun up the singles in January, tried doing a Navajo ply of it and just didn't like the visual overload. So I backed up, spun some dark gray Dorset and did a two ply, then a three ply sample of that. Preferred the three ply and made up the rest of the LNL in that configuration. Incidentally, I have another colorway of the LNL called Violets that I'll probably process in a similar fashion. Probably with a white wool, since there is a little white in the Violets colorway.
-I've noticed that I like to look at my singles for a while before I charge into plying them into yarns. Sample a little of this, a little of that. Find a yarn I like, knit up a small swatch and live with it a while. If I still like it, I'll spin off the rest and stash the yarn.
-I am also starting to catalog my stash in Ravelry. Since I didn't know that it existed until recently, this is an ongoing work in progress. But I'm pleased to have found a system that is workable. I may develop some kind of scrapbook to show the start to finish nature of fleeces to fabrics. I do enjoy the process and being able to keep shreds of evidence along the way is a nice little bit of personal history.
-Once I launch a project, I'm pretty organized about keeping the whole package together while it is in process. I dislike the waste of time when things I need aren't in my working bag. At the moment my knitting bag has a couple projects in it. The instruction/pattern sheets are all on a clipboard together. Swatches and extra balls of yarn are there along with my plastic zipper bag of tools - crochet hooks, needle tips and cables, cable needles, yarn darning needles, gauge measuring tools and such like. I've got a separate bag that I take to work, single project, idiot-proof stockinette. I work on it until I get to a part that requires a lot of attention and switch it out for another piece of idiot-proof stockinette.
-I've got a lot of patterns and books, but I don't carry them around with me. I make a copy of the page I'm working on, and then I feel free to write on it, mark it up and use it to work the piece. When I'm done, some of those pages go back into the original book - notes about what worked, what didn't and where the pattern had things that didn't seem clear - those things are VERY useful if I ever use that pattern again.
So, overall, I may not be completely organized. But I'm getting better all the time!