Composition is the arrangement of objects in a photograph. There are various guidelines and artistic conventions that attempt to describe what makes a good composition.
Rule of Thirds
Place points of interest on the intersections
Imagine that your image is divided into 9 equal segments by 2 vertical and 2 horizontal lines. The rule of thirds says that you should position the most important elements in your scene along these lines, or at the points where they intersect.
Here's how the basic principle behind the Rule of Thirds works: Imagine that your photo is divided into nine squares – three across, and three down, as you can see in the image below.
As indicated by the red dots below, the intersections of the squares are considered visual hot-spots. These are the strongest focal points of your photo and studies have shown these hot-spots are where a viewer’s eyes will naturally want to focus.
When taking your photo, you will want to ask yourself:
What are the most important elements of my photo?
Where should I should I place them within my photo?
Leading Lines
Use natural lines to lead eyes into or through the photo
When we look at a photo our eye is naturally drawn along lines. By thinking about how you place lines in your composition, you can affect the way we view the image, pulling us into the picture, towards the subject, or on a journey "through" the scene. There are many different types of line - straight, diagonal, curvy, zigzag, radial etc. - and each can be used to enhance our photo's composition.
Framing
Use natural frames (openings) like windows and doors to compose and shoot a photo through the opening
The world is full of objects which make perfect natural frames, such as trees, archways and holes. By placing these around the edge of the composition you help to isolate the main subject from the outside world. The result is a more focused image which draws your eye naturally to the main point of interest.
Point of View
Look up, Look down, Lay on the ground, Move to a higher spot to see things differently
There is no law that says all photos have to be taken from eye level and straight on. By taking photos from a different angle, looking down or up at the subject, you can produced a totally new feeling, mood or effect.
Fill the Frame
Get close to your subjects so it fills the camera frame
The simple act of making your subject bigger in the frame involves the viewer at a much more intense level. A chin-to-forehead portrait of an interesting face, for example, immediately puts the viewer eye-to-eye with your subject. A very tight shot of a bear—even if you made it with a long lens at the zoo—creates breathless drama.
Patterns and Repetition
Patterns are aesthetically pleasing, but the best is when the pattern is interrupted
We are surrounded by symmetry and patterns, both natural and man-made. They can make for very eye-catching compositions, particularly in situations where they are not expected.
Symmetry
Balanced and proportional. Equally weighted
Visually weighted the same when the photo is divided down the middle. Symmetry is pleasing to the eye and creates a sense of harmony.