Not bad. It looks amazing, but here a a few problems I noticed.
The biggest problem I can see is that you seem to have misplaced your light source. From what I can see in the shading of your mountains, the sun should be placed further to the right. You can see this more easily by holding your hand over the sun and focusing on the mountains alone. With the sun in its current position, the form shadows of the mountains should envelope more of the mountains. At the same time, there should be large cast shadows over the water, beach, and trees. Creating these shadows would also help give focus to the painting. Right now, my eyes are being drawn back and forth between the sky and the waterfall, and I am unable to tell upon which the focus is. By darkening the water, the viewer would then focus more on one spot in the painting -- the sky. Similarly, the green leaves over to the left side of the image should also be darkened. They are too bright and are distracting for the viewer.
Another tiny problem (I'm just being picky here) is the coastline. The land almost appears to be sitting on top of the water.
But enough nitpicking. Awesome work, and I hope to see more in the future.