Err, Nice drawing there! But I think that there are lots of things you need to improve on. The shading doesn't make sense. And the water looks weird, it's crooked when you look at it. Maybe you should learn about proper shading and light sources. Your lines need more thickness, because they seem to blend into the colors, making them very hard to see. And lastly, I do could not identify that object by the rocks, is it a ghost? Plus practicing does wonders. I hope my comment will be helpful.
RLC
Turned out alright, the colours look great, just work on your line art a bit more. Keep practicing and you'll get better!!!