I was dealing with this and came up with this idea when I re-organized my stash.
I have an area for my stash has been coordinated with what I already have. I put these coordinated colors together and tie them gently with a ribbon. That way I know that pile goes together. Then I just stack them in this area so when I'm looking for fabric for a pattern, I look here first. I still usually have to buy more fabric to "go with" but at least I'm reducing my stash a bit.
We're working on a scrappy quilt at our guild so I bought a colorful border print but was able to pull all the other fabrics from my stash. I was very pleased with myself for being able to do that.... that doesn't usually happen.
Hope this helps!!