As promised, I'm going to describe how I made the "rainy season" purse which appears in the 2009 International Freeform Fiberarts online exhibit.
Yarn Selection
Of course, you can't do freeform without the right yarn, and I knew I wanted a variety of yarns in this one (as opposed to the "summer" purse that is made from one yarn only). And like most fiber artists, I have a pretty big yarn stash, so that was the first place I looked.
I knew I wanted shades of gray along with green to represent the Ko'olau Mountains, my inspiration for the purse, during the rainy season. Most of the yarns were in my stash, but I bought a skein of fluffy "Baby Alpaca Brush" by Plymouth Yarns to represent the clouds which are almost always enveloping the mountain peaks.
Interestingly enough, I ended up not using the yarn I bought and several others, which often happens in these freeform projects. You have an ideal of how you want the piece to look, but it often turns out looking a lot different than your initial conception. But as long as I like the end result, I don't mind.
Scrumbling
The next step was to start making the small pieces that I would eventually sew together to form the flap. This isn't technically scrumbling, but more "organic patchwork," a term coined by celebrated 
freeform crochet fiber artist, James Walters (see the "scrumbling" link).
Using this technique, I created a number of small pieces, selecting stitches based on the yarn I was using. If the yarn was smooth, I created textured stitches like the bullion stitch (that's the dark green stitch at the bottom of the purse flap). If the yarn was more textured, I made simple shapes, like circles and squares, letting the yarn speak for itself.
It's always good to have a good stitch dictionary like the Harmony Guides (out of print unfortunately) or The Crochet Stitch Bible so you're not racking your brain trying to figure out which stitches to use.
Putting the Pieces Together
Once I had what I thought was enough small pieces from which to create a purse flap, I laid them all out (see previous photo) and started playing with them, trying to create a pleasing configuration. But try as I might, I just couldn't get all the pieces to fit together in a way that "felt right." So I let it go for a day or two.
When I tried again, I realized I didn't need to use all the pieces. If a took a way a couple of them, I came up with a design that I really liked.
The next challenge was to sew the individual pieces together. I usually pick up what look like the two easiest pieces to join and sew them together using either a mattress stitch or an overcast stitch. I didn't do it on this purse, but sometimes I will use a shiny yarn to sew some pieces together and let that be another element of the design.
Creating the Purse Body
Once the flap was done, I crocheted a simple body using a smooth, dark gray yarn, in a single crochet 
stitch, making sure the body was wide enough for the flap to rest on. Then I sewed the flap to the purse body, then sewed the purse's side seams together, using the overcast stitch, right sides facing. Then I turned the purse inside out so the right sides were on the outside.
I plan to line the purse eventually. I even created a template or pattern for the lining by outlining the body and flap of the purse on taped together printer paper, then adding a seam allowance of about 1/2 inch all the way around the template.
I've tried sewing a lining onto the body of a purse before I sewed its side seams together. I didn't like the effect it created, so I will probably create the lining first, sewing the side seams together, folding the flap seam allowance under, then hand stitching the whole thing onto the finished purse. The purse body has to be inside out to do it this way, then turned right sides out after the lining is in. But, before I do that, I'll also probably add some interfacing to the flap strengthen it.
Hope all that made sense. Let me know if you have questions.
