Hey, I think you have a really nice piece here!
From some of the lessons I've seen on it, it appears that the more you stay strict on the rules of perspective the more stiff the image will look. After knowing the rules well enough, they can be broken slightly to show more interest.
Also maybe something to think about is, what would this piece look like if the camera angle was tilting up, down or perhaps diagonally. You could also range the size of the trees, increase the contrast of the values or have a more defined foreground, midground and background.
Hope this helps
Chris
