Good start, keep the work up. You could add some structure to the mountains so it looks more interesting.
Just keep working on depth its the hardest part but it'll bring out the life in this picture Try adding some clouds IMO You might want to downplay the light source it looks way overpowering and unnatural (not like its the moon or sun) maybe thats just me... But thats my suggestion Oh and remember to keep your light source consistent something that bright would be shining on the edge of every mountain Just keep filling in the flatness and this will be awesome picture, heck if it was blown up it could he a great wallpaper Keep up the great work ;]
Might want to add some more textures, and like others said, clouds. So far it seems nice, good vectoring ^^