The ones I've seen used applique sunbonnet sue patterns for the outlines, then colored with fabric crayons (or even regular crayons too). They put different textured stuff underneath the fabric when they colored to make different patterns - like window screening, sand paper, etc. They were really cute! I think they heat set them with an iron, and must have used something, paper toweling?, to soak up the extra wax.
Good luck!
sue