Compostion.

http://www.secondpicture.com/photography_composition.html  This link us useful for knowing about composition in photo's. It gives you things such as tips on things to avoid whilst taking photos, and unusual angles that will improve your photo. This photo was taken  by annie liebowitz
I like this photo because its unusual. How the girl is sitting makes the background look tighter.
It is a very dynamic compostion due to the shape of her legs. It contains a lot of diagonal lines. The lines in the body of the van lead the viewer to the subject.