Good characters are real. They’re made from flesh, blood, and ink. They've got families and histories, likes and dislikes. Even the girl behind the register who only says two lines in chapter seven might have a quirky turn of phrase.
If you’re looking to write good characters, you need to get under their skin first. Here's a few tricks to help you do just that.
Strike up a conversation.
Compile a list of questions about anything you’d like to know. Treat it like a real-life interview (or an interrogation, depending).
You might be surprised to find that they seem to come up with some answers all by themselves. Let them. The more genuine and surprising they are to you, the more they’ll be so for the reader.
Don’t simply write down a list of facts for each question. Think how the character would react. If you asked them about their income, for example, would they happily volunteer the information, or would they tell you to screw off instead?
Drawings, images and virtual versions.
These can bring your character to life. Rifle through magazines or Google stock images. I've even seen some authors create 3-D versions of their characters in games like The Sims for a better handle on it.
Check out software like Ultimate Flash Face (http://flashface.ctapt.de) or HeroMachine (http://www.heromachine.com) and create a proper Identi-kit.
Go beyond skin level. If they have a scar, what’s the story behind it? Do they have a favorite piece of clothing? What does it represent?
Everyone's got a story.
Without getting into the nature vs. nurture debate here, our experiences tend to shape who we are—or at least influence how we react to our environment. A bad experience with spiders when you're four might lead to a lifelong fear.
Consider the same thing when it comes to your characters and working out the stories behind them. Never forget to ask why they'd do or say something. Getting into their history, think about where they grew up, who their friends were, what their best and worst memories are.
You're not just creating, you're profiling.
Bark up the tree.
The family tree, anyway. Family history is as important as character history. You don't have to work it out back to the 1700's (unless it matters); a couple of generations back will do.
Basic genetics is a part of this: Hair and eye-color, for one, depend on your genetic background. So do many other traits.
Also consider your characters medical history, both physical and mental. Is there a history of depression, cancer, or genetic illnesses?
In Sherlock Holmes: Game of Shadows there's a scene where Sherlock knocks a tray out of a waiter's hands. Why? To create a surprise reaction—one that can't be faked—to oust the criminal.
The same can be applied to your characters. Write a 250-500 word scene with them in it, and surprise them. Turn their world upside down. This scene doesn't ever have to make the book; it's just there to help you figure out how they'd react to something completely unexpected.
Compile a short bio.
A bio of under 500 words can help you get the flow going. The twist?
Make them write it.
How would your character write a bio about themselves for a dating website? For a professional website? For a magazine or a blog?
I've never liked having to write my own bio, and I'm sure many people feel the same way. It's awkward. Use that emotion and see what it reveals about your character.
Create a blank character sheet.
Round up the most basic details and create a blank template. Fill it in for each character. This is for information like their name, surname, date of birth, hometown, and eye and hair color. You can add whatever you feel is important. It's a quick and easy way to keep track of who's in your story and the basics of who they are.
Don’t worry about incorporating everything into your story. Readers may never even see these bios and interviews and whatnot. But they’ll feel the rounded, live character in your writing, and that’s all that counts.
Besides, it’s wonderful material for some blog posts, marketing, and virtual tours.