Portraits are among the most difficult subjects to draw because, as humans, we tend to be very critical of our own image and the image of those in our species. Attempting to draw a portrait with colored pencils requires special care because colored pencils can have limitations that other mediums do not. Blending can be difficult with colored pencils, and not all colored pencil sets include realistic flesh tones.
Draw the structure and layout of the portrait with a regular pencil before starting with colored pencils. Colored pencils are difficult to erase and portraits are complex. If you choose to skip this step, and move straight to drawing the portrait with colored pencils, you are likely to make mistakes that are you are unable to correct down the road. Draw the structure of your portrait very lightly with a hard lead pencil like 4H or 5H. This way the structure will easily be covered up by the marks from colored pencils later.
Just like a painted portrait, you need to choose a palette of colors in order to give your drawn portrait a cohesive design. Select approximately 10 to 12 related pencils of related colors, and try to use only these colors for your portrait. If you do not have any colored pencils that would make a realistic flesh tone for your portrait, choose unrealistic colors as your flesh tones, such as greens, blues and reds. Choose colors that convey a mood or a sense of the personality of the person you are drawing. Cool colors may be used to indicate peace or depression, while bright warm colors may be indicative of cheer or even mania.
Colored pencils may be used in many different ways to cover a surface with color. While your first impulse may be to simply color in the portrait the way one would use a set of crayons, colored pencils may be sharpened to create fine lines and designs that would be difficult to replicate with crayons. Build up the color on the paper with hash marks, as you would with a pen and ink set. By overlapping different colors in a series of hash marks on the page, you can create a network of complex color combinations that work together to give your drawing depth and visual interest.
Shadows and Highlights
Avoid using black as a color for generating shadows in your portrait, even if the figure has very dark skin. Black tends to make colored images look muddy and gloomy. Instead, consider using a color like dark blue, dark green or dark brown. For highlights on the figure, you may choose to apply color to those highlight areas very lightly. Alternatively, you may choose a light color -- such as yellow, or pale pink -- to represent highlights in your portrait. When applying highlights and shadows to the figure, be careful to blend the affected areas with surrounding areas of color. Use the hash-mark technique to overlap these different areas on the drawing.