The advice is always the same when it comes to backstory.
It doesn’t matter if you talk to other authors, or agents, or editors. They will all tell you the same thing: Know your protagonist’s backstory but filter it into your story sparingly.
I envision backstory like this: It is a beautiful summer day. You hop in your car. You have a beach house. You hit the Parkway, if you live in New Jersey like I do. You’re zooming down the road. Life is good. Suddenly, traffic comes to a halt. That’s backstory. Even if someone magically appeared by your car and handed you an icecream cone--your favorite flavor--you still wouldn’t be happy. Even if you were really hungry, you wouldn’t be happy. Because all you want is to get moving in your car to get to the beach and the water and the sunshine and the cute boys or girls.
Every story you write will have backstory. After all, your characters didn’t just pop onto the scene the minute chapter one began. They existed long before the inciting incident prompted your story into action.
But you must use all your willpower to resist causing that traffic jam.
Alice Orr, author and agent in her book No More Rejections writes: “Include only the bare minimum of background detail necessary to keep the average, intelligent reader from being confused. All else may be preparation for story or rumination on story or noodling toward story, but it isn’t story itself.”
In other words, do not put any backstory into the first three chapters of your story.
Drop it in a little at a time. When it is absolutely necessary to explain something.
Donald Maass, agent extraordinare and author of Writing the Breakout Novel and Writing the Breakout Novel Workbook suggests that you move any backstory from the first fifty pages to Chapter 15 of your story. Then when you get to Chapter 15, see if you still need it.
Down and Dirty, the process of Revision, Step #5 concerns backstory. Identify your backstory, be aware of it, and do something with it. Don’t give your readers traffic jams or icecream cones. They want the beach!