Nice work, especially the drawing of the couple themselves. Everything looks proportionally accurate. You have a really good background and layout, but I think the textures kind of take away from the wallpaper. The bricks look realistic which doesn't match since you have a drawing as your focal. Same with the ground and the grayish texture. Maybe try lowering the opacity or overlaying them over a color layer. As for the bricks, maybe something simpler. There are some good brick tutorials out there. Other than that, the light posts and the fog do look very great though. I'm sorry to say so much stuff to work on, as you said you are new with this type of piece. But I think with a few changes this could be a very nice romantic wallpaper.
And 81 hours in 3 days? That would be like 2 hours of sleep total and nothing but computer the rest of the time! :o
