Vocabulary

Rule of thirds
http://en.wikipedia.org/wiki/Rule_of_thirds
A rule of thumb in photography that an image can be dividided into 9 equal parts and the four points formed by the intersection can be used to align features in the photo. This technique is claimed to cream more tension, energy, and interest than centering the picture.


Frame within a frame- foreground framing
http://www.betterphoto.com/article.asp?id=19
This is when something within a picture is used to highlight a particular part of the picture, or draw your eyes exclusively to that thing. This doesnt necesarily have to be square, but can be something like a window, branch, cave walls, etc.



Leading lines
http://www.aea1.k12.ia.us/lois/leadinglines.html
A line that leads your eye to the main subject of the picture. A leading line can be something like a road, fence, river, tree line, etc.



Close up
http://en.wikipedia.org/wiki/Close-up
Is close up on one object, focuses in directly on the thing. A close up is most commonly a picture of a person's face.
Simplicity



Mergers
http://en.mimi.hu/photography/element.html
Mergers are things in the background that merge with the foreground to produce unexpected results, this is usually undesirable.