For several years I worked with an exceptional acting coach in Los Angeles, Andrew Benne (website here) who teaches a Meisner based acting technique. Andrew coaches consistently working actors and as a filmmaker, I wanted to dial myself in to the rhythms and voice of an actor. The result has been nothing but helpful in my editing career, directing craft, and storytelling ability. If you are a filmmaker, I highly recommend working with a coach like Andrew. It will help you see great performances in your actors and give you skills to help guide those performance when an actor is struggling with moment to moment work. Also for editors in non-fiction, this is very helpful in building dramatic scenes.
One of the basics of Andrew's technique that can be extremely helpful to a screenwriter, is "calling behavior". When you're working on dialogue, a great way to stimulate conflict is to write dialogue that calls the behavior of another character. An extremely simple example: Say two people are sitting across from each other at a dinner table, the mood is sour...
Stop it.
MELANIE
Leave me alone.
CHARLES
You're making that face again.
MELANIE
It's just how I look.
CHARLES
Well I hate it when you do that. It's like you're hiding something.
MELANIE
Quit judging. You're the one that called me.
Charles is calling the behavior of Melanie by accusing her of making a sour face. He's calling her behavior. She's calling his behavior and acknowledging his action by directing him to stop accusing her. He gets more specific and she's put on the defence. He offers point of view "I hate it when you do that" and calls her behavior again this time accusing her of hiding something. She calls his behavior "quit judging" and gives us some more exposition.
It's a very simple scene but has a ton of conflict. Every time a character calls behavior, the conflict escalates. It's an effective technique if you need to punch up a scene. If you saw the movie I edited "Splinter" 
the word "firecracker" comes up between the characters Dennis and Polly. Dennis is calling his impression of the behavior of Polly. It instantly escalates the argument.
It's important to note that it doesn't have to be a serious scene either, you can call behavior in comedy or sad scenes. Friends can be sarcastic, worried, empathetic, or any number of emotional states and still call behavior. Give it a try on your next script.
For more information on Andrew Benne visit http://www.andrewbenne.com/
