Really really rough job...tons of mistakes in coloring can be seen,like under the eyebrow,a small solid blue shape can be seen,and also edges around the face are messy...
The eyes need a bigger shine and more defined shape,it's all just shaky...
The hair looks strange because the hairs are not continuing all the way from top to bottom..I think a much smaller strokes would also make hair more detailed and better..also more variety in color...
What's wrong with her finger,it's all spiky and it doesn't have a nail?O_O
Also,that chain she's holding totally blew it,it looks different than everything in the wall,stands out too much because of that texture,and doesn't seem real at all...

The shading is good,but it could be more smooth,you should have blurred and smudged it more,to get rid of those circles from the brush...that can be seen best at the left part of the nose..

Just,a really messy messy wall...could have been so much better,if you just paid attention to details...but don't give up,it's hard to color something like this with a tablet...you need more practice^^
Ganbatte xD