The idea is to fill an area by coloring the fabric behind the embroidery. Usually, this means that only the outline is embroidered, with some details added. However, tinting isn't only for coloring inside the lines. Many artists use this technique to create spectacular backgrounds, borders, and accents for their embroidery work.
Concentrate on the basics. If you are just starting to color, keep things simple. Forget shading, burnishing, details and texture _ start off by block coloring and concentrating on keeping between the lines. Block coloring is simply the practice of taking your colored pencil and filling an area completely and evenly with that color. Get to know your pencil, feel the weight of it and practice control. Simply filling those spaces with color whilst trying not to go beyond the lines will help you master control and prime you for learning more advanced techniques.