Arm's too skinny and long. Perspective of the face is wrong. I wouldn't worry about colouring or shading just yet. You can't hide fundamental errors regardless of how pretty you can make it look.
My opinion on drawing something you're not used to is to first ditch that urge to make something look "perfect" and by that I mean making the linework look super clean. The nitty-gritty temptation of constantly correcting the slightest mistake is what stops you from analyzing the whole picture when drawing from reference, especially when you're inexperienced.
I'm struggling with drawing soemthing myself at the moment, but I'm slowly throwing away that desire to create a clean drawing for the time being until I know I'm doing something right.
Right now, you need to focus on analyzing what you see and accurately putting that down on paper. If you look at her right arm, you can see you forced one section to be long so that her hands could sit flat on the desk. The left side of her cheek is forced out too much unlike the photo. The "rules" of perspective state we shouldn't see that much of her left cheek. See your reference pic.
Keep sketching for now. Colouring can come later.
I treat all animes and manga equally, its just a matter if its good or not after watching the whole series. 
at least don't forget to report how good you find it when you're done, compared to whenever the heck you watched it before... which brings me to, how long ago did you watch Rayearth, VB?
