I tried to work a little bit at home to see whether I can improve the picture without losing the feel of immediacy. I strengthened the body and the arm. The main improvement is the negative space I added to the left corner of the picture under the elbow, echoing the inclined shoulder line of the model. That also supports the triangle formed by the arm and the head. I think this little space strengthens the entire composition. At least I feel I learned something from this little exercise.