You have an uber amount of contrast from the shadow left from the figure and the figure herself. But barely any contrast in the actual model. I would say to deepen some of the shadows in the model so it flows better and doesn't look washed out the way it is. This happens when the reference photo was taken with a flash which this certainly looks like was the case. Plus if you darken down the form it will give you a chance to pull out some powerfull highlights. On another note, the elbow at bottom of the page looks too sharp and that same forearm looks really butch. Since its sitting under her other arm and under her breast, it is probably falling under massive shadow to complete darkness. If you bring that down it wont look as beefy.