Strangely, in my rise as a writer, I find myself in the minority on the crucial subject of structure.
Because there is no end of struggling writers in this world. But I am surprised at just how many of my fellow aspirants take the idea of structure for granted. "Why are you so concerned with it?" They ask. "Everyone knows that your first concern needs to be building characters. That's the orthodox position."
These same people then go on to lament their own inability to get their characters right. What a struggle it is to get them to be interesting! Why do they sound wrong? Why do they not step off the page the way they are supposed to? These writers know it can be done. They've seen their favorite authors do it again and again. So what is stopping them from doing the same thing?
Well, I'll tell you.
Characters Don't Exist until the Structure Calls for Them
And if you don't believe that, consider the following scenario:
Your protagonists are handcuffed to folding metal chairs, being tipped ever so gradually and carefully over the lip of a reservoir dam. The villainous Don Martine laughs at their misfortune as he gingerly undoes the bungee that is the only thing keeping your heroine from falling headfirst into the watery abyss. This is the moment your readers have been waiting for---the one that will decide if Nathan truly loves Jessica enough to sacrifice his own life for hers. It's all been set up so perfectly that there is no way of telling just what is about to happen.
But then, out from the shadows pops a girl with bright red hair, striped stockings, wearing a tutu and black nail polish whom the reader has never, ever, ever encountered before.
"Who the flying frack is that?" Don Martine asks. He turns to Nathan. "You know this weirdo?"
"Don't look at me," Nathan says. "I thought she was some kind of panic-induced hallucination."
Luckily, Jessica is in the know.
"Oh, don't worry about her. That's just my cousin, Cheryl. You'll love her. She's super interesting. She collects branded towels and has an eating disorder. She's also got the mind of an eight year old and sometimes receives psychic visions from my dead father. Plus she's really good at sewing and has a crescent birthmark around her belly button. Isn't she so well designed? Wouldn't you love to see her get up to some shenanigans?"
"Wait, so is she here to rescue us?" Nate asks.
"Oh no. She's not the rescuing type. I just thought that now would be a really good time for you two to meet her. Let's all stop what we were doing and become acquainted."
Your characters are then left to ponder this new development, and all the unresolved tension concerning your protagonists' survival and ultimate destiny is thrown onto the backburner while we get to know Cheryl.
It goes about as well as you'd expect.
But it can't be helped. Because if creating interesting characters was really more essential than structure, then you should be able to drop new characters into any part of your story. Never mind that the reader is more invested in the characters you've already got. Never mind that you actually have to interrupt the flow of the story to introduce Cheryl, because dadgummit Cheryl is just so darn interesting. She's not your typical character and therefore must immediately become the center of attention.
DON'T WE ALL NEED A LITTLE MORE CHERYL?!?!
A Good Structure is where Good Characters Come From
In all seriousness, you shouldn't introduce new characters during the climax of your book, or anywhere in the last 20% or so of the text. There are exceptions, of course, such as a real villain getting unmasked or a well foreshadowed reveal. But even then, it is the structure that determines when each character will appear, for characters are carved out of that background structure, much like how gingerbread men are cut out of dough.
Your protagonists get cut out in the first act. Your side characters and comic relief come into play after that. And all of it is dictated by narrative structures as old as time itself.
Because characters are only worthwhile if they go through character arcs. And character arcs are nothing more than your story's structure making itself known. You are developing individual people here, and their various ups and downs need to have the proper rhythm and cadence if they're going to resonate with the reader.
That's why writers who ignore the principles of structure end up with broken characters, needing to be stretched and twisted in unnatural ways to make them fit into the story. Wanting your characters to be the highlight of the narrative is natural, and even smart. But it can't be done if you don't have a structure in place to support the existence of all these people. Their limitations and lifespans must be dictated by the confines of your structure, and not the other way around.
If you can save yourself from making this rookie mistake, you'll have that much of an advantage when your story is finally put out there, among the countless other titles fighting for recognition.