Some real Problems
For the most part, you can tell that it is Tricky. The down side is that the character has a unique enough design that it is pretty hard to botch.
I wanna discuss color first, mostly because of one area. The hair is blending in to the flames of the background too much. Even with the line art it is difficult to tell them apart. Because of this and because the use of the same color again and again for different materials and textures I can pretty safely assume that you have a very limited marker selection. Either that or your too lazy to make sure you grabbed enough variants from the marker rack. IF their was a color to defiantly ditch it's the purple on the character and sign.
The anatomy of madness characters isn't that hard to do either, but you kind of screwed up on the hands. One being much larger than the other is pretty obvious. I think you should have gone with a bit bigger hands anyway considering the character.
The costume I have little to say about, but over all it's kind of "Meh"
The background and stage is kind of a problem. To start you are lacking a good perspective on the stage, and the grid you placed on it makes it obvious. As for the flames, we have already discussed the biggest problem of color already. Perhaps some dramatics and some white added to the flames would have helped.
You mention being in a art class already. Make sure your teacher is showing at least the basics of Design, Color Theory, Perspective and the basics of general arts. If not then you are going to have to learn on your own if you want to get better.
3/10