More information on continuity. http://en.wikipedia.org/wiki/Continuity_(fiction)
The rules and shots of continuity editing
The 180 rule°
This rule states that there is an invisible 'line of vision' between any two actors in a film, this line of vision sets up the scene, showing who is on the left and who is on the right in the scene. The rule uses this line as its basis, stating that the camera must stay on the side of the line of vision that it started on, only being able to move 180°. This means that the characters in the film do not suddenly swap positions in the camera view, thus confusing the audience.
Diagram of the 180° rule:
For more information:
http://www.solutioneers.net/cinema/axis.htm
The Shot-Reverse shot
This is a film technique that involves showing a shot of one character looking at another character and then another shot of that character looking at the first character. This shot indicates that the characters are looking at one another, even though the viewer can't see that they are.
Diagram of the shot-reverse shot:
For more information:
http://www.artoftheguillotine.com/index.php?page=shotreverseshot
The Match on Action shot
This shot occurs when consecutive shots match up an action, in the first shot, an action with start and in the next shot (or multiple shots) this action is completed. As an example, in the first shot, someone goes to sit down on a chair, the next shot is the chair being moved into position and the next is the character sitting down on the chair.
For more information:
http://www.infoplease.com/cig/movies-flicks-film/cutting-for-content.html