Justwannaquilt mentioned using paint swatches. I just read a tip in a Lynette Jenning's home decorating book that I'm going to try when selecting my next quilting fabric. She says to take a sample of the fabric you want to match to the paint store and find paint chips that come as close as possible to the three or four dominant colors in your sample fabric. On each paint chips there will be other coordinating colors. So with 3 to 5 colors per chip, that will give you 9 to 16 color possibilities. She was talking about matching sofa fabric, but I don't see why it wouldn't work with quilting fabric.