Pretty nice man. One thing I see off is the shadow of the tree in the middle. It should not be as far to the right, move it more towards the center. Try to keep shadows directly with the light source. Also, I would try and clean up the BG some. Its really kind of blurry IMO. Other than those two things looks pretty nice man. Just keep in mind shadow and light sources. When it comes to Large Art, those two things can make your art look good or bad.