Rule of Thirds:

This is not so much a rule but more of a practical guideline. Having the subject in the middle of the frame is boring. And if all subjects are in the middle of the frame, then the viewers' eyes will not move as the images change from one shot to the next. This may cause your audience to fall sleep. So we need to mix up the placement of the subject.

Since the placement within the frame is important, you need to put some consideration into where you will put your subject. To make the decision easier, we split the frame into three sections vertically and three sections horizontally. Thus the frame is split into thirds. When shooting, try to put the subject on one of the lines instead of the middle.

Artists discovered that each of the areas have a meaning. If you place the subject to camera left while looking camera right, this gives a feeling of wanting or adventure. If you put the subject on the camera right side while they are looking camera right, the subject appears to be trapped.