Few minor points, but very realistic.
Proportion is a bit off (between eyes - face is too thin, back line, right shoulder, or lack of), although its tricky drawing from photos because they create an illusion of proportions that real life doesn't. Assuming you're using a photo. Also I'm really unsure as to what's going on with her chest?
I am, of course, being highly critical here, that's just how I review and I wouldn't review you if you weren't very good anyways. Hair is very difficult, looking rather limp here but it looks like that's just the model, the attention to detail there is great. You definitely have awesome shading skill with pencil, I do love the contrasts within the shading that give it a very definitive 3D effect, especially where you've gone really dark. Go even darker and bolder with your shading! I also think you could transfer those skills into watercolour really well.