Bad dialogue is the fastest way to lose a reader. Good dialogue makes a script unputdownable. Here are the five rules every working writer eventually learns.
1. Characters never say what they mean
In life, we hide. We deflect. We say "I'm fine" when we're not. We talk about the weather when we mean the marriage. Subtext is the gap between what's said and what's true — and it's where great dialogue lives.
2. Every line should do at least two things
Reveal character. Advance plot. Build a relationship. Plant a seed. Land a joke. Set up a payoff. If a line is doing only one of these, it's probably cuttable.
3. Read it aloud
Your ear is smarter than your eye. Lines that scan on the page often die in the mouth. Read every scene out loud. If you stumble, the actor will too.
4. Cut the first line and the last line
Most scenes start a beat too early and end a beat too late. Try removing the first line. Then the last. Often, the scene is sharper.
5. Distinct voices
Cover the character names on a page of dialogue. Can you still tell who's speaking? If two characters sound the same, you have one character with two names. Voices come from rhythm, vocabulary, what they avoid saying, what they fixate on.
Aaron Sorkin's characters all sound like Aaron Sorkin — but they sound like different Aaron Sorkins. Tarantino's people speak in long arias. The Coens' speak in pauses and dry understatement. None of these is "right." But each is consistent inside its world.
The exercise
Pick the worst scene in your script. Cut every line in half. If a character said five words, give them two. If they said two, give them a look instead. You'll lose nothing important. The scene will breathe.