I'm only just learning to do this stuff, so I'm no pro, but my first thought on this is to look for a reference. Searching "Ocean Floor" comes up with some great references
Color:
The first thing to notice is that underwater sand takes on a bluer color. Using that pinkish red is more akin to a desert, whereas a yellow might make more sense on a beach.
Perspective:
Since this scene is side-view, it would help to texture the sand almost like rolling hills when viewed from the top of a building.
That said, I did a quick mockup of what I think might work. I didn't texture the whole thing... just a small spot, but it should help give an idea of what I'm getting at.
I tried using a green-blue sandy color as the base and progressively bluer tones for shade etc, then I made the lumpy thing. I also used dithering on the lower lump and no dithering on the higher one just to see if that might make a difference. Lastly, I changed the overall outline to the same color I used for the deepest shade, but you can just stick with black. I was just experimenting.
Here's what I came up with... you know... just for funzies?
I'm thinking I should have used just a little more contrast, making the shades a bit deeper... but who knows.
I also want to point out one thing (and it's only because I noticed it)... the lighting isn't entirely consistent. With the rocks, for example, you took the exact same pixel layout but flipped it, thus putting the light source at top left for some and top right for others. I like the variation from switching the outline, but it might help to readjust the light source when you do. Just a thought
/blabbering
Logged
I'd love to be a part of this and all, but I can't take it. I wish I wasn't so touchy, but the fact is -- I am! So to save you all the trouble, I'm heading out. Thanks for the help so far! It really means a lot
You're all beautiful, wonderful people with beautiful, wonderful art. Keep it up!