When deciding on a theme for your screenplay, make sure it indicates the type of character journey your protagonist will have as they move towards story conclusion. For instance, the theme for a film about a shy teenager chasing their dream to become a glam-rock god could be “You must be willing to be loud to overcome your shyness.”
Theme is expressed through the protagonist’s character arc as they move from being a flawed individual to realising their shortcomings to becoming a better person. How this plays out across five acts:
Act 1: The protagonist is unaware of the theme and unknowingly resists it.
Act 2: They have experiences that helps them to understand the theme, and their resistance lessens.
Act 3: Through conflict, vital knowledge is revealed to them that enters them into the theme.
Act 4: They must finally come to grips with what’s inside to accept their new self.
Act 5: They finally realise the truth behind the theme’s message and fully embrace it.
So, on this theme, “You must be willing to be loud to overcome your shyness,” the protagonist might start with the point of view that being loud is just another way to make a fool of yourself. Such a view indicates a past trauma and what the protagonist must overcome mentally and physically as the story progresses forward.