The most frequently quoted rule of composition is of use of thirds. Imagine your picture being divided equally into nine rectangles, three across by three up. The main features of your image should be placed not in the center of the frame, but on this dividing lines. Ideally the subject of the picture should be located on the intersection between two of these thirds. The use of thirds is very much guide - anywhere between thirds is and quarters is just as good. Though useful, this does not always have to be applied. For example, a close up picture the main feature could be placed in the centre.
written by: John Ellis DIGITAL PHOTOGRAPHY