The Rule of Thirds

The Rule of Thirds is a compositional rule found in many of the visual arts. The rule tells us to place two imaginary lines placed at equal points along the horizontal and two equal lines on the vertical. This splits the image into thirds both along the vertical and horizontal. The rule then places emphasis on placing important compositional elements along these line or intersections. The rule of thirds helps to discourage the placement of the subject in the centre of the frame, which in turn helps to create a more striking image.
The following  before and after images will show this rule in effect.