Continuity editing is basically when the editing is smooth and flows so it is easy for the audience to watch. For example cuts are not jumpy or staggered in anyway but all lead on from each other in a pleasing way.
180 Degree rule
The 180 degree rule or sometimes known as the line of interaction is simply an invisible line that the camera cannot cross when two people are having a conversation. If the camera does cross this imaginary line the characters talking will be looking in the wrong directions and this will distract the audience.
Match On Action
Match on action is when a cut is made when a movement is taking place and the movement flows from one cut to the next. It is done so as you watch it you don't notice the cut and you don't get distracted from what is going on in the film.