If you look through quilting magazines, most have a method for letting you know whether the quilt would be a 1 thimble, beginner, 2 thimble - beginner with experience, 3 thimble intermediate quilter and 4 thimble advanced; or something similar to that. I have a stash, however, when I go to make a quilt, I start with a focus fabric, one that will be the main fabric, and then pull fabrics that would go with the focus fabric. Fabric has a code in the selvedge that tells you what colors were used in the fabric - take that as your guide and you can't go wrong. It is like being a kid in a candy shop when you go into a fabric store, but most will have fabric arranged by color or type and if the staff is being less than helpful I would speak to the manager for advice.