When done with the background, we go into doing the character. First we use a medium to large size hard brush at 100% opacity to fill in the colors we want for each part. Zoom into the part you want to color and brush away! Erase away any spill out with a hard eraser. Remember to do each color on a different layer!  

Photoshop tool used: Brush Tool/Eraser Tool  

Tip: Press [CTRL]+[+](plus) or [CTRL]+[-](minus) to quickly zoom in or zoom out.   

When you are done, you should have your character filled with the base colors. Be sure that every part is filled with a solid color (even the whites).

Photoshop tool used: Brush Tool/Eraser Tool

Tip: If your PC is unable to support a very large number of layers (it may start to respond slowly), merge the layers with items far apart to save RAM and space.

Determine the light source and we can lay on the shadows and highlights! I always start with coloring the skin. Using a soft large brush at 40% - 45% opacity, I roughly brush out the different tones with darker or lighter skin color.  

Photoshop tool used: Brush Tool  

Tip: Use the Eyedrop Tool to select the base color and select different tones using the color picker.  

Select another darker skin color, fill in the details for shadows using a small hard brush at low opacity and Multiple Mode. Work on a new layer grouped to the base color layer.  

Do the same for the highlight details, but using a lighter skin color with Screen Mode.  

Photoshop tool used: Brush Tool