I have a pretty modest stash and generally keep them sorted by colour, encompassing all different "brands" of that colour (prints, tonals, batiks). I also sort fabrics for planned projects together and separate from the rest. I may change my method as my stash grows (which is happening quickly - I recently ordered 36yrd of various fabrics - prints, tonals, blenders, batiks - and inherited a bunch from my great grandmother) and I don't have a "plan" for ANY of them, lol.