Here's a link for a fantastic Colour Wheel System:
http://www.gilbertdesigns.net/
The "Eye for Color" System provides an enormous selection of colour(s) - primary, tones, shades, pastels, warms, cools, etc. and each wheel is interchangeable.
It can be placed next to fabrics when doing initial layout selection and/or can be carried with you to your LQS when shopping for fabrics.
I've purchased the entire system and am extremely pleased with the fantastic colourway selections I now have at my disposal.