The document discusses various techniques for mixing and layering colored pencils to create depth, texture, and realism in drawings. It explains that all color mixing uses primary colors of red, blue, and yellow, and secondary colors are created by combining primaries. Various layering techniques are described such as hatching, cross hatching, scumbling, burnishing, and directional lines to build up color and texture through overlapping layers. Examples of drawings demonstrate how these techniques can be used to render different surfaces and textures like fabric, wood, and fruit.