This article first appeared on the Writer’s Fun Zone in January, 2012.

We’ve all been there. You’re reading a novel. The back cover copy–or a friend or coupon or clever marketing strategy–persuaded you to buy it. And now on page 15, you’re stuck with a hero who’s too stupid to live or a heroine you’d cross the street to avoid in real life. What are your options?

Do what I do: throw that book down the stairs and stomp on it as you head out the door. (Not if it’s on an ereader or tablet, it goes without saying.) Your other option: keep that book until it’s the only thing that separates you from a dark and stormy night, and try it again.

As a writer, though, you don’t want to give your readers heartburn. How do you create characters that readers can empathize with, root for, and–most of all–come back to?

The first step is to create characters that you can empathize with, root for, and come back to. If you hate sitting down to write every day or if you think your hero is a jerk, trust me–your readers will think so, too.

That doesn’t mean that your characters have to be like your Uncle Ned, who took you fishing as a kid and gave you nickels for ice cream. Real life, strictly interpreted, has a way of not translating to the page very well. Just think of most conversations you have with your significant other: the utility bill, the thing your boss said, what’s for dinner. Not exactly the stuff of the next blockbuster thriller.

Like anybody else, a character is defined by what he does. It seems obvious, but if you need an action hero, he has to show action, and not just in the kidnapping scenes. He can watch a football game on TV, but only after he’s done a 10-mile run. What else would an action hero do? Take risks, make decisions, right wrongs, and protect the helpless. Show your hero doing these things in big and small ways. To be sympathetic, your hero needs some flaws, too. If he’s decisive enough to take charge, he’s probably also at least somewhat obsessed, self-righteous, and obstinate. Be sure to put your characters in situations that show their virtues, as well as their failings.

But there’s more to characterization than what your people do. If your hero takes crazy risks, why does he do that? The why of behavior is motive. Your characters are defined almost as much by why they do something–or mean to do something–as the actual activity.

To give your characters depth–and tell your readers why they do something–give them a past, a reputation, friends, relations, pets, habits, patterns, hobbies, skills, disabilities, chronic diseases, food allergies and anything else you can think of. If your heroine recoils in horror from a plate of homemade cookies, she’ll be more interesting to your readers when you reveal that she’s anorexic or rude or allergic to peanuts. Or maybe she was just terrorized by a gang of goobers in her crib. Whatever her motivation, show it to your readers, so they come to understand why your characters are behaving the way they do. That’s the road to empathy.

Nonfiction, anyone?

Up to now we’ve been talking about writers who focus on fiction, but characterization applies to nonfiction writers in some ways, too. The main character in a nonfiction book is you, the author. You’re the character that needs to be empathetic, someone the reader wants to come back to. Your energy and enthusiasm, your unique personality, and your flair for storytelling will determine whether your book is dusty and dull or thrilling and exciting. If you don’t believe this, look at old New Yorker profiles–the ones from the pre-Tina Brown days. Those writers could take topics that seemed like lumps of coal and turn them into diamonds.

Of course, if you’re writing an academic monograph for which the sole purpose is to get tenure, that monograph had better be as dull as dishwater or you’ll be out on the street sharpening pencils for a living before you can say jumping Jehosaphat. Everybody else: you might be writing nonfiction, but you’re telling a story, shaping a narrative, and having a conversation with your reader. If the topic weren’t interesting, you wouldn’t have picked it. So talk to your readers so they’ll find it as interesting as you do.

Remember: what did your characters do, and why. It doesn’t sound like much, but it’s everything.