Step 1: Outline your hair with a dark color of your choosing for the hair using the pencil tool.

Step 2: clean up the edges with white, and fill in the hair with white, taking out the bald head.

Step 3: Fill in the white hair with the same shade of the color you're using, but lighter, using the paintpucket tool.

Step 4: Get a slightly darker color, but not as dark as the outline, and make shading where locks of hair would fall and at the edges of pieces of hair to make them look 3 dimensional.

Step 5: If the colors contrast too much, get a color in between to shade it a little better. If not, get a color slightly lighter than your base color and put in some big highlights where the light would hit the hair.

Step 6: Get a color lighter than that and go back over the highlights to make a more intense highlight where the hair would be closer to the light source.

If you want a little more realistic look, use smaller chunks of hair and make strands stick out in some places.And if you have room, or would like more shine, just keep getting lighter in shade.