Dialogue comes from the character, but action comes from you, and the words you choose to describe that action have everything to do with developing your own unique voice, but until you become the master mechanic of that secret recipe, you must rely on your character.
Say, for example, your character is a drug addict. Since there are many kinds of personalities, buying different kinds of drugs, at different socio-economic levels, and in different social groups, it just makes sense that the specific drug jargon used by a thug on the streets of the Bronx would be quite different from that of a privileged Hollywood socialite. If it’s cocaine they’re after, what do they call it: coke, candy, blow, flake, dust, powder, snow, sugar, etc?
These details are important because the generic noun – in this case “drugs” – is too vague, and even the more specific noun “cocaine” is not good enough when describing it within it’s distinct world. Instead of just writing “cocaine” time and time again, figure out which noun is specific to your character. If your street thug’s word of choice is “blow” or “candy”, then embrace that and use it while describing it in the action as well.
But don’t stop there. What about the dealer? What’s that dealer’s self-proclaimed professional image? Would he call himself a supplier, a distributor, or an import/exporter? Or if your character is an assassin, does she see herself as a merchant of death, a murder mechanic, or a facilitator of fatalities? You get the idea – these are concrete descriptive words, that when chosen wisely can make a world of difference in your script – both with action and in dialogue.
But selective word choice is not limited to nouns alone. Whatever the scene might be, whatever the action… try to think of ordinary everyday nouns, verbs, and adjectives that you can change to make more authentic to your characters and their world. Instead of saying car, home, girlfriend, mad, sad, or glad, etc, ask yourself what other appropriate word(s) you can use. Doing this can drastically improve the writing without adding unnecessary length to the page.