I'm fairly happy with this. What have I missed?

The elbow?

:p

It's a great shot, well done to all!!

Have to agree about her elbow, if you had moved models left elbow back more and not pointed it at camera.
Would also like to see more fill light from the right side of photo to light the dark areas and help balance out the bright areas. [Dark areas such as inside models right leg, left side of models face and out side of models left arm.]

I wish you well

First, I think you're completely justified in being happy with the image. I like the image as well.

I agree with the others that pointing the left elbow outwards would have helped the image.

I would like to see the image with her head rotated a few degrees to her right. I don't know whether that would really be better, but I'd enjoy seeing them for comparison.

I'd also like seeing a version where she's looking upward and at the light.

The background is interesting. I get a suggestion of a corner of walls behind the model and a corner between the floor and each of the walls. I like not seeing obvious corners. That the floor corner on the left side of the image doesn't correspond to the wall to floor corner seems odd. I like the background, but I'm still trying to decide how much.