Backstory explains how and why your character is the person she is: shaped by a background built on family, education and past experiences.
The most interesting backstories are the secrets revealed under the greatest stress when her morality, beliefs and values are tested to the extreme.
Never give the audience anything that they don’t need to know. Past secrets get revealed only through current action.
What backstory does the character keep a secret from others? Why? What would make her reveal this?
We’re curious about the past, because we know there are interesting stories behind every decision. Some might involve intrigue (“She was forced to leave town’) or romance (“They met at the top of the Eiffel Tower when they were both students in France”) or corruption (“The politician used government money to pay for his Bel Air home”).
The current situation is a result of decisions and events from the past. And the choices that were made determine the choices your character will make in the future.
To understand your character, you just need to answer three questions:
What moment defined your character’s relationship to her parents?
What moment defined her greatest desire?
What moment defined her greatest fear?
These three moments reveal where your character comes from, what she wants and what holds her back.
We all have history. No matter where you start a story, you are never starting at the beginning. Well-handled exposition can bring perspective, dimension and needed context to your story.
The hardest thing when starting to write is to stop your story turning into a biography, because the minute you start, you’ll want to write “Wait until I tell you about her father… and what she was like at school… and the day she was born.” Don’t fall into this trap of ‘establishing’ things. It is always better if your reader has to wonder what’s going on, than to have everything in black and white.
Having said that, the backstory is often the trigger that starts the story; the moment of decision unknown to the other characters that starts the ball rolling
Keep it brief. Bring in backstory when it has bearing on what is happening at present.
Use Arguments. Convert your exposition to ammunition and let your characters use backstory to win arguments, saving the most damning piece of information for the last line. It can be information given as an emotional outburst turning frustrations into information like ‘I’ve been paying your drinks bill for ten years!’’ or in turn it could be used to justify your character’s actions. “Look, this is just the way I was taught.”
Use Humour. Exposition can be more interesting if said with humour revealing your character’s attitude.
Backstory is the answer to how the character reacts.
It explains how and why and who they are. Write up a history, even if you don’t use in the story. In particular, write about secrets as it is these that explain the character’s decisions, helping to dramatise and motivate the turning-points.
The question to ask is ‘What does this information do to the character now?’ If it doesn’t affect the action, then leave it out.