Good writers do not litter their sentences with adverbial garbage. They do not hold up signs reading “laughter!” or “applause!” The content of dialogue ought to suggest the mood.
– –James J. Kilpatrick
Nouns, verbs, are the workhorses of language. Especially in dialogue, don’t say, “she said mincingly,” or “he said boisterously.” Just say, “he said, she said.”
— –John P. Marquand
Dialogue which does not move the story along, or add to the mood of the story, or have an easily definable reason for being there at all (such as to establish important characterization), should be considered superfluous and therefore cut.
— – Bill Pronzini
Remember that you should be able to identify each character by what he or she says. Each one must sound different from the others. And they should not all sound like you.
— – Anne Lamott
Dialogue has to show not only something about the speaker that is its own revelation, but also maybe something about the speaker that he doesn’t know but the other character does know.
– – Eudora Welty