I think the main problem is that your piece does not have a lot of depth. You placed the shadow underneath her wrong, it looks like she is floating especially her legs look like she's holding them up in the air. The foot from the front leg should align with the line of her butt, because now it looks like they're on a different height. The face looks a little bit unproportionate, the glsses feel like they are "tattooed" on her face instead of lying on her nose, make sure that they follow a line.
The colors and rendering look great, but be sure that everything underneath it fits so that you get a better end result.
I would draw over but I'm not at home right now.
Good Luck!