|Greetings from the Critique Club!
While I like this pose and your use of the umbrella in this photograph, the background does not work for me. I believe the blown out sky detracts from your image, or, at the very least, does not add anything to it. I believe this same pose set against a different backdrop may have worked much better. In general it is a good idea to pay careful attention to one's background. I find that backgrounds are ignored more frequently than anything else by photographers. Careful attention to them can improve a photograph dramatically.
The model's chest is also lit slightly more than her face, which tends to pull the viewer's eyes there. A fill flash or a little dodge work in post-processing may have helped to correct this.
This photograph has potential, though, and I encourage you to continue your model work. You have working with the models down cold -- just pay attention to what's behind them. I believe it will improve your work dramatically.