The exposure is determined by 3 different elements. These elements are ISO, Shutter Speed and Aperture. Each of these change the way the image looks and is taken but also affects the brightness of it. This means you need to have a balance between settings to keep the picture clear.
Examples Of Exposure
This image is very over exposed. As you can see its hard too make out a clear idea of what's in the picture. This can be adjusted by tuning one of the settings from the exposure triangle elements.
This is an example of the iso being taken down but the shutter speed was still too high. This lead to being able to see an after image of someone walking.
Symmetry is the act of dividing a picture into two images that are mirror images of each other.
The definition of a viewpoint is a way of looking at something. As you can see from the image below, instead of just taking a picture of the girls the photographer takes a picture showing the view of the phone camera which makes the phone the main focal point
RULES OF THIRDS
The rule of thirds is applied by aligning a subject with the guide lines and their intersection points, placing the horizon on the top or bottom line, or allowing linear features in the image to flow from section to section.
Leading lines are a good technique to use to get the picture to have a clear focus as it leads the viewers eyes towards a certain area.
By using eggs its easy to see how light positioning can change the atmosphere of an image.