camera shots

match on action
either an action commenced in shot A is completed in shot B, or an action in shot A is mirrored by an action in shot B, for example when we cut from character A in location A reading a letter to character B in location B reading the same letter. 
This creates the impression of a sense of continuity- the action of carrying through creates a ''visual bridge'' which draws the viewers attention away from the slight cutting or continuity issues. Match on action portrays a continuous sense of the same action rather than matching two separate things.

shot reverse shot
Shot reverse shot is a film technique where one character is shown looking at another character, and then the other character is shown looking back at the first character. Since the characters are shown facing in opposite directions, the viewer assumes that they are looking at each other.
A shot showing what the character is supposedly looking at either a point of view or over the shoulder shot is followed by a reverse angle shot of the character themselves looking at it, or of the other character looking at them.

180 degree rule
In film making, the 180-degree rule is a basic guideline regarding the on-screen spatial relationship between a character and another character or object within a scene.
This allows the audience to have a greater sense of location in the scene in terms of what may be off screen in some shots for example in shot reverse shots.