I'm also doing something else unusual, which is my approach at this illustration. I'm doing the background by itself first, as apposed to just doing the piece all together. I wanted to see how it looks alone before I lay out the characters too.
Anyway, I still have to work on the water and a few other textures before I get to the characters, but here's what I've got so far...

feel free to comment or add any thoughts.
Peace,
James