I talked earlier about the power that a writer has in using action and visuals to frame a scene for a viewer. We played with framing scenes by changing the kind of club the cops were staking out, by changing what the cops look like, etc. This is the real meat of a screenplay. Experienced screenwriters know that this stuff, when used effectively, communicates immediately to an audience on both a conscious and subconscious level. Dialogue, on the other hand, requires that they both listen carefully and remember. On top of that, they have to interpret the dialogue the way you intend. It's more difficult, more risky, and just not as entertaining.
So now let's talk a bit about how to right a good action line. There are two ideas to keep firmly in your mind: SUCCINCT and SET UP.
SUCCINCT. Trained readers typically skim and visualize a script. They have neither time or interest in reading your script like a novel. Want to know how to lose them?
Angela delicately pushes her hair into place to cover her nerves as Brandon sits down to his untouched plate of food. A wave of emotions ripples across her face in a way that reminds Brandon of his mother. He grimaces.
Yes, a viewer may read all this into a scene. Yes, an actor may well have worked out all this backstory. But it's the actor's job to ripple waves of emotion across the character's face. It's your job to build the set up that communicates the difficulty.
Does the movie viewer have access to your action lines? Nope. How are they going to figure out what you mean? With a little luck, the actor may decide to accept your puppeteering rather than engage their own craft. But basically, you're punting. Rather than work the meaning of the scene into the set up or the actions, you've pretty much just stated your goal and called it a day. Guess what. The reader is looking at the feasibility of your script. It might seem like a paradox, but by relying on your brilliant prose, you're punting on the screenwriter's #1 goal: communicating visually.
Now look at this:
Angela glances at her watch.
She glances at her watch again. Still 8:16.
Brandon re-emerges from the bathroom, slipping his CELL PHONE into his pocket as he exits.
He smiles weakly as he sits down at the table.
First thing to notice. My action lines are more or less a shot list. A script is basically a set of instructions for telling a story, right? Second thing: you can SKIM through mine without missing anything major. I communicate visually that she's anxious by having her look at her watch twice. I communicate the backstory by having him slip his cellphone in his pocket. We're done.
This brings me to the SET UP. Writers often have trouble decided what to include; either puppeteering every gesture and facial movement the poor actor has, or simply writing out dialogue, hoping that the producers share your assumptions. This uncertainty can be a symptom of a bigger issue: not knowing what a scene is for.
There should pretty much always be one simple, clear reason for a scene. If you don't have that, you probably don't need the scene, or you need two shorter ones. Once you've nailed down the goal of the scene, nailing down the action lines should be relatively easy. How much to describe about the restaurant or the food? Well, think of how your characters react to it. What's the import? Is it clear what I'm trying to do? What's the one, simple, skimmable phrase I could add that would make the set up crystal clear?
Let's take an example. Writers will often wonder how much they should include "He smiles". The rule of thumb: is it part of the set up? Is it essential that the actor smoke the cigarette, smile, nod, look wistful, etc. at that particular moment? Say a character is walking down the street with his girlfriend on a sunny day, talking about their upcoming honeymoon. We know he's smiling. So leave it out. It's already implicit in your set up.
When would you use it? How about:
EXT. CEMETERY -- DAY
Fred, dressed all in black, holds up his sobbing mother as his father's coffin is lowered into the ground.
As she buries her face in her hands,