Here's a work in progress of a Cthulhu Painting I'm working on.
I started with some rough painting of the kind of water I wanted, then I moved on to manipulating a photo element I got from CGTextures.com
Next I laid in the rough shapes and built on them until I had this rough painting.
Then I added some wave effects
Then I threw in some seagulls to add depth.
And now I've decided to make it a wider image, so this is where it's at now.
Here's a rough sketch that I did while I was considering how to tackle this painting. It needed to have some kind of environment, so originally I was thinking of showing him on the sea floor in R'lyeh. Here I was just experimenting with some lighting choices and trying to think of how to convey a murky underwater environment.