Don’t have characters tell each other things they already know just because the reader doesn’t know those things. For example, if two sisters are talking, it’s highly unlikely that one would say, “When Mom and Dad adopted our brother John, I was devastated.” Find another way to convey relevant relationships or bits of backstory to the reader.

Another no-no is to have an exchange between two people weighed down by repeatedly calling each other by name. “Hello, John.” “Hi, Sharon.” “How are you doing, John?” “Oh, Sharon, I am so low I have to reach up to touch bottom.”

A third negative is putting in greetings and leave-takings that are pro-forma, tell us nothing about the characters, don’t move the story forward. Just because they would happen in real life doesn’t mean that every amenity has to be spelled out to the point of diluting the scene.