After looking at it for a while, I really like the dark shimmer. It tells me that we are in the environment of space and this being is superior by his elegant appearance. Keep it up.
Coloring is like a muscle, especially with digital programs, mastering that with nothing but a mouse is advanced. Keep doing this, and don't stop even if you think you're not improving. Little by little, you will develop your own techniques and study others trying to improve yourself as you move up into a further grade. This is actual pretty great if it's your first time.