All good books have one thing in common–they are truer than if they had really happened.
This is especially true in dialogue because dialogue is not a transcription of a conversation. It is sharper, more focused, and often has more subtexts going on than real speech. It is interaction (read conflict) between your characters.
You’ve probably read dialogue where the words and their underlying meaning are at odds, or where the tension between the characters is so tight you feel you are in the room with them. That kind of dialogue takes work and focus. It’s more than just hearing voices in our heads or channeling our characters onto paper. There is a bit of science behind the voodoo. There are principles, keys that help us unlock good dialog. Understand these keys and good dialogue is no longer something that shows up only when the muse does, or worse, happens by accident. It becomes something you can create at will.