This tutorial shows you the basics of how I color my work.
I placed the basic colors where I want them to be, just to see how they would compare to one another. I can change them as I go along. Doing this helps me to make sure that the colors work together.
I began adding the shading to the skin. I used a darker color than the skin and used the watercolor brush at low opacity.
Added the shading to the hair, then the highlights. For the shading I used the watercolor brush. For the highlights I used the 'lighten' tool. (Be careful with using this tool, because sometimes it makes an image too annoyingly bright for the eyes.)
I shaded the tail with the watercolor brush then on a new layer added the scales with a darker color to areas with a lot of shade. Added some light again with the 'lighten' tool.
Shaded the rocks with watercolor. Made sure to add the shadows near her body.
Colored in the sky. A simple blue color and worked in some clouds with a few swirls with the watercolor brush. Changed the color of the flower to blue with a watercolor brush. Made the fins see-through by removing a bit of the fin colors with the eraser. I cleared some room to draw in the water.
Added in the water for the last step. Again, using the watercolor brush and the highlights with the pen tool. :) All done!