Take a 6 X 24" ruler. Lay it on your fabric making sure the fold is exactly square, then basically roll your fabric on it. When it's all rolled, slide the ruler out and fold in half. This works from 1/2 yard up to about 4 yards. for longer pieces, fold the fabric in half lengthwise (so you wind up with a piece that's about 11" X 5 yards). then wind this on the ruler.
This makes all your fabric roughly the same size and will store easily on a shelf.