Probably the single hardest lesson for me to internalize in writing was that you don’t design a character you design a character arc.
One reason you as a writer might end up stuck with a flat or boring character, or one that just isn’t doing the things you need to create a vibrant plot, despite working out all the details of their life for hours, is because you’ve made the mistake I always do. You’ve made a character who is a blend of all the characteristics you envision for them, rather than saving some characteristics for the end of their journey.
What do I mean by this? Maybe you envision a character who is a handsome prince, honest, brave, and true. In your plot, though, he’s going to be an antagonist for a bit but you don’t really want him to be seen as a bad guy, necessarily. But when you drop him into your story, he’s just… there. Being honest, brave, and true.
That’s because the prince has no character arc. He is a static figure, a cardboard cutout.
Let’s go a little deeper with a great example of one of the best character arcs in YA animation: Prince Zuko. He is, objectively, honest, brave, and true (to his cause of finding the Avatar) from the outset. But he’s also a dick. He’s a privileged, imperialist brat, who is rude to his uncle and vicious to our protagonists.
By the end of the series, though, Prince Zuko is still honest, brave, and true, but he’s also a good person who has learned many lessons over the course of his trials and obstacles. He has failed over and over again at his initial goal of capturing the Avatar. He has failed at winning his father’s regard. He has failed at numerous smaller goals of day to day adventures. He has learned from all of these. We have seen his journey. But, if you started your vision of how to write Zuko from who he ends up being, he’s got nowhere to go as a character.
It’s not just about what flaws he has corrected though. It’s about what lessons about life he has internalized. What flawed views of the world he has corrected and how.
Rather than saying, “The character starts out a dick and learns to be nice,” be more specific. “This character starts out believing the empire he is loyal to is morally in the right for its conquests, but over the course of working for that empire’s ruler and seeing his cruelty first hand, not to mention fighting the empire’s enemies and mingling with its civilian victims, he becomes a better person and learns the error of his ways.”
Already, right there, you have more than a cardboard character. You have a character who has an arc that molds to your plot.