Maybe you’ve heard the saying that a script is just a blueprint. If so, forget it! The first goal of your script is to be a great reading experience.
Later there will be a production script annotated by the director and others involved in planning the actual production once your script has sold. That’s the blueprint.
There will never be a production script until and unless there was a great selling script--the version read by agents, script editors, producers and others you want have get excited about your work.
With that “blueprint” comment in mind, many screenwriters are afraid to write descriptions of the action and of the characters in a vivid way. Big mistake!
The great playwright and short story writer Anton Chekhov gave this advice to a writer: “Don’t tell me the moon is shining, show me the glint of light on broken glass.”
The way to make a character or a setting or an action come alive in the imagination of the reader is to provide specific details. Compare these two descriptions:
Howard is a so fat he finds it difficult to walk.
Howard wheezes with the effort of carrying his weight. Every ten steps he has stop and lean against the nearest wall.
Not only is the second description more specific, it brings in another sense--the sound of wheezing. The more you can bring in not only what things look like but also their smell, their feel, their taste, the more real they become to the reader.
Often the best specific to mention is one that is unexpected. For instance, it might be that despite his bulk Howard has dainty feet.
Later the director and the actor playing Howard may decide not to have him stop every ten steps
Different details will have different effects in terms of how the reader perceives the character or the setting. For example, if we want the reader to feel some sympathy for Howard, we might show him enduring the embarrassment of having to buy shoes in the children’s department.
One warning: don’t overdo it. Adjectives are especially dangerous! One usually is enough. “Grimy fingernails” is fine; “Grimy, misshapen, yellowed, gnawed fingernails” is too much.
Adverbs can be even worse--generally it’s better to describe the action rather than characterize it. For instance, instead of “He eats the donut greedily,” you might write, “He stuffs the entire donut into his mouth so fast that jam squirts out of his mouth.”
Checking to make sure that you have been specific in your descriptions is one of the key things to do when you go over your first draft. If you want to see how it's done, read some of Chekhov's short stories. They constitute a great master class.
And remember: nobody enjoys reading a blueprint.