Upside Down Oceanside

Done as part of a practice session with poses of 10 minutes in length. My current goal is: Improve at correctly controlling & understanding 3-point perspective in a scene and/or environment. Hey everybody, Polyvios here, and this is my study. That's of an oceanside. I drew it from an upside down greyscale. What do you think? Am I really seeing it as I'm really drawing it? Could it have been really keener? Or am I all set?