I do find the color wheel to be of help. But with the fabrics having the color chart on the selvage is the biggest help of all. I like to look at the selvage and see where all the colors are in the fabric. If a color is the majority of the fabric I see what they complimented it with and choose fabrics with that dominant color. If I'm doing a quilt in all shades of one color I make sure they have the same undertones of blue or yellow. Color is the biggest thing most quilters struggle with. Look at home decorating and fashion magazines for how they use color.