Framing is a technique used to focus the viewer's attention upon the subject.
With two people in a scene ‘The Line’ is an imaginary line cutting through the eye lines of the characters. It is important when cutting between shots not to cross the line as it will totally disorient the audience and make it very hard to follow what is going on. Once you have decided on one shot all other shots must remain on that side of the line. The only way to cross the line is to either move the camera during a shot or move the characters (effectively taking the line with them). If you were to then cut back to a shot on the previous side it wouldn’t work so all shots from then on would need to also be on the new correct side.
Cutting across the line could be used intentionally to trick the audience. Although should only be done if absolutely necessary as if not done right can come across as a mistake.
Rule of thirds
For over shoulder shots give two thirds to the forward facing character and one third to the ‘over shoulder’ character.
Keeping characters off centre is more picturesque.
For close up give the character two thirds with one third of open space.
Deciding which side to put the open space on can control how close we feel to the character. Open space in front can draw you in to a character, open space behind can give the impression of a character being very closed and private.
Here is a short video demonstrating the Rule of Thirds 
Spatial Continuity is the technical name for the understanding of the scene’s layout in the viewers mind when we cut between shots. If not done right it can make a scene impossible to follow. Watch any badly choreographed fight scene and you’ll know what I mean.
The easiest way to solve this is to start with a Master that clearly shows the layout of the room. This can make things so clear that you could probably even get away with crossing the line without too much disorientation. The main drawback with doing this is that it can takeaway any sense of mystery about a scene making it impossible to withhold certain information from the audience. This is what is called open and closed framing.
Open and Closed Framing
- Open Framing is when we don’t have everything we need to understand what we’re seeing. We’re only seeing a small part of the bigger picture with a lot of the key information being out of the frame.
- Closed Framing is self contained where everything is clearly in the frame.
In short Open Framing create questions and Closed Framing give answers.
The Camera Height is important
- The closer the shot it is best to gravitate more towards eye level.
- The wider the shot it is best to gravitate more towards waist height.
But changing the camera height can also affect a character’s superiority or inferiority. (noticeable more in close shots) A low angle looking up at the character can make them seem bigger while a high angle looking down can make them seems small. For examples see this clip  from A Little Princess (1995) or Tapped (2007).
Changing the height of the camera in wider shots is more noticeable when there is a clearer indication of perspective. Try to give your shots more depth by ensuring there are lines of perspective indicating a vanishing point or including something in the foreground. This is very important when doing a crane shot otherwise it can feel like the camera has hardly moved.