I agree with what everyone else has said.
Just a quick pointer with pencil sketches or any sketches really;
try to make the strokes conform with the shape of the thing you're trying to convey. I mean, make the lines go around her arm as if her arm was a three dimensional object, it really helps to add depth and make the image seem less flat. For instance in
[This] image, the artist has used strokes that work with the form, rather then random ones.
This technique is what separates an awesome pencil drawing from a great one.
Hope it helps!
I'm really glad to see someone drawing realism though, it's harder than anime, but it's worth it in the end!
Good luck!