umm...
between the mountains and the trees, the transition is kinda... not so good.
the sky is good, but i suggest making the mountains have more space and depth and range. Prehaps making the fog closer, so that the mountains are covered in fog. making them seem farther away.
seeing the texture of the mountains in the back really killed it for me. work on it though..it has epic potential. Like add a bright sun, and move the mountains back or make the fog closer and it could be epic.