Si nce this would be more of a critique on art as opposed to wallpapers, i'll probably be focusing on that more.
which may result in me being much harsher. but please don't take any offense to it, it's just suggestions.
i really love the sketchyness of the drawing. i'm always a fan for sketchyness. also, the colors are really nice as well. limited palletes are always a plus. the perspective isn't awful, but drawing it freehanded, especially in photoshop isn't so much an excure for perspective being off. you don't need a ruler to get it right. but since you know about the perspective, and seem to at least understand the idea and how to do it (unlike most people) i'll leave it alone.
the depth is really nice. the way it fades out into the background...i've always liked that. gives more focus to the front.
i think the black ines in the front could have been toned down a bit. making them a really dark brown, or a really dark purple or something usually helps it blend in better. right now it seperates a little too much. you also seem to randomly lose her legs behind the fence/railing. even some subtle hint-lines would have been nice. and now i'm gonna just mention a technical gripe. the second red pole...the middle one. i know you used photoshop, so i know it wa sthe spacing of the brush, but it really bugs me x_x
the rest of it is so smooth and that part just jutts out. i'd go back and fix it.

ever try using painter for the digital art?
i'm just getting used to it, but i find it works nicely sometimes, especially with the feature of being able to change the texture of the paper. :3

overall, i really like it. and i will be faving it :D