There are lots of ways to make a screenplay character three-dimensional, and one is using symbols. Of course if the symbols are too on the nose they can detract, but here's an example of a subtle one:
Actor Paul Scheer told Fast Company magazine: "My character [in Black Monday] wears a wig in the show, and that was a conscious [choice] because when we first start talking about how he’s wrestling with his sexuality, I wanted that wig to represent the idea that he’s already hiding. On the base level, it’s like he’s not even comfortable being bald in this world."
I don't know how many people watching Black Monday would pick up on that, but a lot of times we register such clues subconsciously.
Here are some other ways of revealing character:
What kind of clothes do they wear? Are they still wearing the style they wore twenty years ago, or are they desperate to keep up with the latest fashions? Do they care more about the label than the clothes per se? Do they try too hard to be quirky--or to avoid being noticed?
What kind of decorations and furniture do they have at their residence? What kind of painting or photos are in the background? The total absence of any decoration also tells a story.
What kind of accessories do they choose, such as watches, rings, bracelets, etc.? For example, what does it tell you when a guy wears a Rolex? (It ain't about telling the time.)
I find it helpful to think about such things because they make the character more real to me. The more real the character is to you, the writer, the easier it is to know what they'd say and do in any situation.
