28) Emphasis

Emphasis can be created in many ways, take for example contrast. Contrast can show emphasis by pointing something out that does not fit into the surroundings.

The red ball obviously does not fit in which is one reason that your eye is drawn to it, the other is that it is in the middle of the photo.
Another route to showing emphasis would be to isolate something. By making it stand alone and not be part of a group you add emphasis to it.

In the picture below there is a technique employed that is called Emphasis by Placement. This is created by having many elements pointing toward one single focal point to draw attention to it.