This is one concept I keep going back to, over and over, as I write. Everyone is the center of their own universe, their own life story. Even bad choices are made for reasons that made sense at the time. Why is this important? Because it makes every single character in the story being told far more interesting when you think of them as someone with a life story.
For the Hero, this should be obvious – but sometimes the protagonist suffers from having no life story outside the Plot of the novel. This is actually one of the traps I keep falling into, and probably one of the easiest mistakes to make. Think about it for a minute – did the Hero of your story drop everything to answer the Call to Adventure? (Even if they were forced to for some reason?) Does your Hero ever look back or try to pick up the pieces, or do they fully embrace their role as the Protagonist?
Even the Hero becomes much more interesting when they have a life to live beyond the Plot of the story. What did they do before? What did they want to do with their life – what were their dreams and aspirations? Will the Plot get in the way of their dreams or help them achieve them?
The answers can be contradictory, too. People are contradictory! A Hero that dreamed of exploring and gets a chance to go on a Quest can still miss home while he’s on his journey.
Minor characters also benefit from this idea! The supporting cast should have lives outside of the plot, too. Ask the same questions of them as you would the main character – why are they here? What are they hoping to achieve? Did they answer the Call willingly, or were they forced to take on the role they have in the Story?
The cast becomes more compelling when each of them has a slightly different set of answers.
Even extremely minor characters – people that only appear briefly in the story – are the Hero of their story. You don’t have to know the whole story, but even a small glimpse into their life can make them feel like a round personality.
The innkeeper wanted to be an adventurer when he was a kid, but he decided he’d rather have a steady job instead. He got married and has a kid now, and he’s happy, but he still gives the Heroes a wistful look as he passes them their drinks… and then tells them to keep it down when they go to bed. Maybe he tells them his wife gets angry when rowdy customers wake his kid up at night, maybe he keeps that to himself, but either way he’s a more compelling character than he could have been.
Perhaps the most important characters to remember this concept with, though, are the Antagonists. They should think they’re the Heroes, too – even if they’re doing bad things, they should have good reasons for doing them. (Even if those reasons are selfish.)
An easy trap to fall into with the Antagonist is to give them a tragic backstory in an attempt to make them compelling. There is some truth to this idea, certainly, but it becomes a problem when it is used as an excuse. It’s more compelling when they struggle with their inner demons, too.
What does the Antagonist hope to accomplish? How do they justify their actions? Are they too proud to admit they’re wrong? Are they ignorant of the consequences of their choices? Do they just not care?
The Antagonist becomes much more interesting when they think they are the Hero. Maybe they were forced to pass the point of no return. Maybe they’re protecting someone. Maybe they think they have nothing left to lose… but they’re doing the right thing, from their point of view.