Well, it misses the shades and the highlights which are the most important part imo. They give depth to the colouring and add a whole another level of coolness. I know it seems hard at first but just do them and you'll learn. Pick a light source and do the shades accordingly. In the tutorial that I linked to you there's a section where it guides you through the process and helps a lot with the time spent on it, and it has also a few fondamental tricks (lock layer etc...).
Other than that just one thing. Use different color for each character skin. It's a common mistake that everyone makes at the beginning but it's really important 'cause otherwise they all just look the same and it looks dead at a first look. Just pick a different tone of the same color or if you know that the character has a particular skin tonality do that one.
I did a lot worse when I started btw. So you're good.