Build your colors gradually, and layer them. Apply a light undertone, and build darker colors slowly on top. Crayons can actually be more difficult to layer with due to the high wax content. Don't confuse them with colored pencils! If you want the "look" colored pencil, just use that instead.
How to Crayon Tint. To crayon tint, your embroidery, start by transferring your design to the fabric. I recommend using a finely sharpened regular pencil, as it won't require water or be affected by ironing. Place the fabric in an embroidery hoop so the back of the fabric can press against a flat surface and color the design as desired.