This is such a gorgeous drawing, I find it hard to believe it's done in class! But I think everything is basically perfect! The only thing I can see I think I would change would be maybe just a little (I do mean a little. not very much at all) less shadow on her arms, and that's all I can see worth changing, other than that I can't see anything else. This is such a beautiful drawing, something like this I could never do. The technique used for the wings looks great! I've never seen anyone else use it! Keep up the good work!
Hum ok ...Sorry if my english is bad , but I'm french so ... In first place , your drawing is verry beautiful to watch , and I love angels. It's very difficult to make a critique on this because you draw much better than me , I think the only problem I could see is the shadows : On the top they are much darker than the dress ones. But that apart I don't think you need a critique ^.^ Just one question I can't see what she holding one her hands , is it a mouse ?
Continue to make your beatiful work and make us dream !