The 8th element of composition is
Use of Negative Space (or "White Space")
open space brings the eye to where you want it
|This is a group of balloons we spotted in the sky...they were tied to some kind of a sign. Mysterious!|
|I know that this isn't the nicest photo to look at, but I was proud of the fly for holding still for me.|
This element is pretty easy to understand. You can use blank or empty space in your photo to bring attention to the subject. I think this element would work well with a shallow depth of field. Sorry I didn't have a photo to demonstrate that... :S
One more post left...on Symmetry!