In both fiction and nonfiction, building a sequence is more than just cutting from wide shots to close-ups ("cutting" is a synonym for editing). Editors want a sequence that flows naturally—as if it is all happening continuously. And that means knowing the best moment to make the cut from one shot to the next.

To the right is a sequence that does NOT have this flow. It’s two shots of a man picking up a phone. Watch it. The first shot ends when the man’s left hand is moving toward his face. When the second shot begins, the man’s left hand is on the phone. So when the two images are cut together, it seems abrupt.