Brief Color Tutorial

Just a few brief things about coloring digitally that I put together, things that have helped me and I figured might help others. Basically, I broke it down into a few ideas, suggestions, and methods. As always, there isn't just one exact, by the book method for coloring a picture.
It starts with a don't list. Remember, the tools can be used correctly. I'm not saying you can NEVER use them.

EDIT:
What happened with the shadow/highlight on the girl's face? It should be way more dramatic than that! They look the same but I don't know if I have the original file anymore.