Continuity Editing

Shot reverse shot

Shot reverse shot is a technique where the camera first shows Character A looking offscreen and then shows Character B looking offscreen in the opposite direction, making it look as if they're looking at each other. Sometimes the shoulder of the other character can be seen at the edge of the shot, as if the camera is behind the other character looking towards the first character as if they're looking in on the conversation. 

Shot reverse shot 

                                                     Match on action

Match on action is a technique where the first shot shows an action which cuts to a shot portraying this action. This creates continuity in the scene and helps the action 'flow' rather than jump to different cuts. 

Definition of a match on action shot with an example.

By having a character begin an action in the first shot and carry it through to completion in the next, it distracts the viewer from noticing any slight continuity error between shots. 

In the 2nd shot we see the character jumping, which is continued in shot 3 with the completion of the action. 

180 degree rule 

The 180 degree rule is a rule that states that the camera should stay on one side of an imaginary line. This imaginary line is perpendicular to the viewpoint in the camera's establishing shot, reinforcing the continuity of the scene. This is effective in car chases, conversations and sport for example, so as not to confuse the audience. 

The camera must not go in the red area, it should always stay within 180 degrees. 

Example of the 180 degree rule

Some editors break the rule "to create effect" although this is uncommon as most people wouldn't want to disrupt continuity or confuse their audience.