Characters

Character

• They're exterior needs to clearly show their situation, values/personality, & other important things.
• Their interior needs to be shown through their surroundings and exterior to avoid excess exposition.
• When designing them you need to create a realistic and believable backstory and clearly understand how that has shaped their personality, values, situation. How do they react to events that cause excess of emotion in any direction? A character will react differently to things depending on their past experiences so they are important to have in mind when writing them, even if they are not necessarily needed for the film.
• A good idea of family, culture, and heritage also helps as this further shapes personality and identity. 
• Identity (or lack of) is key to a character.
• Everything that has happened, is happening, and will happen will change them. Where they've been, where they are, and where they'll go also forms them. They must be kept in mind when writing, especially at key moments for the character(s).

When I've made character profiles for models, I've always created a detailed backstory and family characters for them. The majority of this is never included but it helps me to shape them convincingly.