I know. As I already states, I just started blocking out the colors and added a single layer of shading to each color. Wanted to know if the shading was alright so I could continue without having to hear the shading's wrong later on.
I don't really agree with that type of thinking. When I do paintings in photoshop I accept the fact that the shading isn't going to be right at first. Don't waste time trying to get things perfect in the beginning. Have things make sense and have the composition (and anatomy) work. After that then you pretty much start correction things until you're done.
Shading and highlighting really shouldn't be two different steps. They are harmonious! I hope that's a word.
I hope you bump up the contrast as you go, the shading on the skin seems... weak.
Shoulders should probably be a bit wider, just a little. or a smaller head.