In memorium - Dave Stevens

This one is respectfully dedicated to the memory of Dave Stevens (1955-2008).

This is an older piece from a photo done when trying to follow in the giant Stevens footsteps - i.e. taking inspiration from his influences, the finest in illustrative cartooning, such as Frazetta, Wood, Crandall, and Raymond - I quickly realized that the Stevens approach is very demanding, requiring more dedication, discipline, and academic technique than was feasible for my talents to pursue - making my admiration for what he accomplished even greater.... but I still want to try a more proper tribute illustration in a short while...

Need help with piece (background for now)

Alright, I'm having a ton of trouble with the background. The colors look muted and faded out. The horrible looking brownish blocks on the right are supposed to be mountains, but I can't seem to figure out how to pain them. I know Xia posted a vid on painting mountains, but I still didn't quite get it, heh.
Can't paint buildings right either.

Also the perspective looks off. I'm trying to make some fantasy city covered with trees but I don't know how to pull it off. Any help would be greatly appreciated.