I know, I know, it's always my fault. ;D
First of all I'd like to mention that I really, really like the sketch, the pose looks really natural and has a wonderful smooth flow in it.

The head is very nice, too. Because it looks really realistic on the one hand but on the other hand it's obviously your style, that's a really great thing.
What I'd like to criticize are the shoulders ... or more the breasts? The right shoulder is lifted more than the left one, if you did that on purpose then the breast's aren't completely right. Always remember that when lifting your arm, your breast muscles and breast are lifted as well. The problem here is that the left breast seems to be bigger than the right one because it's not lifted. Try drawing a horizontal line as help there and you will see what I mean.

And I can't get rid of the feeling that the right arm is a tad too long, but I might be wrong.
And I really like the form of the legs as well, but they might be a bit too short. But that is just a matter of taste.

Anyways, great sketch, I'm looking forward to see more! *hug*