Trying out some new brushes, still getting the hang. From my point of view the shadows are a little wonky, could be darker not sure. If anything sticks out at you feel free to drop a line.
You could apply some more atmospheric perspective and wrap the shadows down in the valley more around the landscape, but first work on those rocks. Almost all of them look like penises, especially the one in the bottom right corner.
Actually, I'll offer the same advice I frequently do...work on your basic drawing fundamentals - with traditional media. Stay away from digital tools unil you have a solid understanding of drawing and painting. If you don't know what you're doing with a pencil you don't know what you're doing with Photoshop.
Three good starter books I recommend are "Imaginitive Realism", Drawing Scenery" and "Drawing Essentials".
Haha, well I made some quick adjustments mainly trying to get the dicks out of the back ground, which I'm still laughing at. This was just a quick speed painting I whipped up in a hour or so. Thanks for the book suggestions hopefully they have them at the public library when I have some time. Open to comments.