It looks like there might be some potential here but there are definitely some problems.
As mentioned, the horizon is tilted...yet the model is vertical. That really creates a feeling of visual tension.
It's overexposed, from the washed out colors to the blown out highlights on her skin.
The front of the model is in shadow, some fill flash or better yet a reflector could have helped this.
I think the worst part is the model's face. She is probably a very pretty girl but we can't tell because she is looking down, possibly with here eyes closed and her mouth in a weird position. If the horizon was level it might look like she had just passed out and was about to fall into the water.
All that being said, you are pretty close to a really good picture. In this situation, it might look better (IMHO) if you moved around the model so that the sun was more behind her but not in the frame. Then used a reflector of some sort to light up her face. Maybe a little bit of flash. Of course getting her face in a more flattering pose would help as well.