Composition

Contrast

When trying to emphasize a subject, it is best not to photograph it against a cluttered background. Compare a photo of someone taken at an amusement park, with dozens of people in the background, with a portrait. The portrait has a very subdued background that lets the observer concentrate on the subject. This is not to say that you should try to make the background as plain as possible. Other people and objects in the background can make the photo more interesting, but taking a moment to think of how the photo will look will give you the chance to improve its composition. Even in the amusement park example, the photographer can try to find a less cluttered background to improve the contrast of the photo. Another method would be to 'crop' the photo, so that the subject fills more of the frame. The subject can also be emphasized using an exposure control such as selective focus (depth of field).
Rule of thirds

When framing your photo, it is usually best not to have the subject exactly in the center of the frame. A subject that is off-center encourages the eye to explore the photograph. Following the rule of thirds can help you compose a more artistic looking photo.

Mentally divide the scene into a grid, like a tic-tac-toe pattern. This will consist of two vertical and two horizontal lines. For photographing the horizon, align the horizon along the top or bottom line, depending on whether you want more of the sky or ground in the photo. You should end up with a photo that is proportioned with two-thirds sky or land (depending on the one you wish to emphasize), which is much more pleasing to the eye than having the scene split evenly.

With vertical subjects such as a people, trees, buildings, and monuments, align them with the left or right imaginary line. When photographing people, have the person face slightly inward, towards the center of the scene.

Experiment with placing the subject at the intersection point of the lines, which are strong positions for your center of interest. With some compositions, you can utilize both the vertical and horizontal lines and intersection points.

Framing your Subject

A subject is framed if the photographer is able to include and crop surrounding objects so that the resulting lines and shapes lead to the subject. For example, you could take a photograph through a wooden fence overlooking a horse in a farmer's field. The fence will be cropped, so that not much of it is visible, because its role in the photo is to frame the horse in the field. You can follow the rule of thirds here as well, having the horse slightly offset from the center of the frame.
Lines and Curves

Lines and curves present in your photo, whether in the subject itself or in the area leading to the subject, lend a pleasing aesthetic quality to the scene. As in the rule of thirds, the eye is naturally drawn to asymmetry, following the lines and curves to examine the scene. This can add interest to an otherwise simple image and can emphasize a particular feel in the subject.
Point of view

When you look up at a large object such as a building or statue, the object conveys a message of dominance and power. Conversely, when looking down upon a subject, such as small children or pets, the message is more deferential or humble. Try taking photographs of these subjects at their eye level for a different, perhaps more realistic perspective. You will notice a difference.

Experiment by shooting buildings from a distance using a telephoto lens, and then shooting upwards from the structure's base. Each view will give you a vastly different perspective.

source : http://www.timebanditphoto.com/composition.htm