Walter Murch is widely regarded as one of the greatest editors in the modern age of film. Known for his work on the Godfather, Ghost and Apocalypse Now, Walter Murch's editing and sound design techniques distinguished career means that he is looked up to by a lot of budding editors in today's world.
Murch hard at work.
Murch's breakdown of how editing will work in a film involves a lot of areas that have to be covered, ranging from emotion to the story of the film itself.
With regards to emotion, Murch has always asked "Does this cut add or subtract emotion?" Murch believes that no matter what content you put into a film, what it all boils down to is how the audience reacts to it all; how does the audience feel after watching something you have created?
"If they are feeling what you want them to feel all the way through the film, you’ve done about as much as you can ever do."
Rhythmically, an edit must be especially tight in order to reduce sloppiness and creating an unintended discomfort in the audience.
“(a cut) occurs at a moment that is rhythmically interesting and ‘right'.”
Eye Trace is also important, as the audience must be able to smoothly follow what the central focal point with ease,
The finger is the focal point here, and must be edited
on the movement in the next shot...
...like so
The 180ยบ Rule is essential to be followed in most circumstances, as the audience's sense of space when watching a film is catered to when following the rule. An imaginary line must be drawn from one character to another, usually in a conversational scene.
The camera must stay on one side of that line to keep the audience from being disoriented, unless you intend to and the the rule can be broken.
The Rule in action.
Very importantly, the edits you make must propel the story forward effectively. If a scene you are editing does nothing to advance the plot, it shouldn't be included; the audience will not want to see it.
Murch is definitely a figure to research into if one is looking for tips and rules of thumb for editing techniques and reasons for editing film scenes in a certain way.