Nothing about writing fiction is easy, but everyone who’s ever set their mind to the task knows that the most challenging part of writing a good story is creating interesting and believable characters. Character is the heart and soul of fiction, the one essential element that on its own can sink a work or make it soar, regardless of how strong the other elements might be. Think of the best works of fiction you’ve read. What immediately comes to mind? If the work is truly great, or even just really good, it could be any number of things: vivid setting, poetic language, a haunting scene, a startling and unexpected twist in plot. But without a doubt, standing front and centre in your memory of that work will be an unforgettable character.

What does it take to create a character in whom a reader will want to invest time and emotional capital?  Where do memorable and enduring characters come from? These questions have no definitive answers.

More than any other aspect of writing fiction, creating character is personal. There’s no formula for writing great characters and every writer has his or her own approach. Some writers start by envisioning the person they want to write about. Others start with situation. A young pregnant wife discovers her much older husband is having an affair with a woman who is closer to him in age, a woman she has always regarded as a mentor and friend. The story could start with the wife (let’s call her Lianne) making this discovery and then struggling with what to do next. Lianne loves her husband (let’s call him Philip), and the other woman (Christine) is someone whose friendship she values. Being pregnant limits her options. Her marriage to Philip is a good one, or so she thought. At this point the writer is facing some crucial choices, mostly involving Lianne. The reader’s response to Lianne depends on what the writer has her do, think and say. If Lianne goes on the offensive and attempts to gather evidence of the affair in order to divorce Philip and take all his money, we might see her as resourceful, or we might see her as calculating, especially if the story has told us or implied that Philip has always treated her well. If Lianne barges into Christine’s office and goes ballistic on her, we might see her as impulsive or irrational. If Lianne blames herself, grows despondent and contemplates suicide, there’s a chance we’ll regard her as weak. If she goes out and has an affair of her own—pregnant or not—we might look on her as someone who gets payback. Other factors will come into play as well and influence how we feel about Lianne. If she and Philip live in the city where Lianne grew up and she has a tight network of friends and family to help her through tough times, that’s different than if Philip has forced her to move to a town where she doesn’t know anyone and feels isolated and lonely.

So how does the writer make the right decision? What is the right decision? Is there a right decision? Is there a wrong decision?

A lot depends on the kind of story the writer wants to tell. Lianne sad and lonely is a very different story than Lianne cunning and vengeful. Writers of genre fiction don’t have to face this issue. But writers of literary fiction face it every time they sit down at the computer or typewriter because there are no rules and the stories we tell are as rich and varied as the number of lives being lived on this planet. This is where the writer must find a way to learn everything about his characters inside and out, to understand who they are as individuals and intuit what they’re going to do under any circumstances. This is where the writer has to trust the power of the imagination. If the writer doesn’t really know Lianne but plows ahead with her story anyway, he might find himself undecided about how she reacts when she discovers, say, that Philip has bought a gun. If the writer hesitates or gets stuck on Lianne’s response to this discovery, it’s likely he hasn’t imagined her clearly and will probably start doubting everything he’s written about her to that point. But if the writer trusts his instincts and allows his thorough knowledge of Lianne to dictate her next move—or, better yet, if it seems as if Lianne is acting on her own, independently of how the writer might want her to behave, making a surprising move that the writer hadn’t anticipated but which seems inevitable—it’s a sure sign that the writer has a firm grasp on the character he has created.

In my experience, fully realized characters will tell you what they’re going to do, or just go ahead and do it, and you have no choice but to follow their lead. The worst thing a writer can do is push his character in a direction she doesn’t want to go. It's also very difficult for a reader to sympathize with a character who acts against her own best interests.

None of this really adds up to practical advice.  So I’ll offer this.

Readers can relate to characters whose concerns mirror their own. We all know what it’s like to worry about money or love or keeping our children safe or whether or not the car’s going to start or writing an exam when we haven’t studied enough or if we’re going to get an interview for that job. In other words, we all know what it’s like to have something to lose. Ask yourself this: who’s more interesting, the young, pregnant woman who’s alone and thinks her philandering husband wants to kill her, or the young, pregnant woman who coolly drains her husband’s bank account and flies off to the Cayman Islands? Whose story has more dramatic potential? In each instance, what’s at stake?

The way I see it, characters who are vulnerable on some level are the ones whose stories make the strongest impression on the reader. This is the Damsel in Distress motif, which has been a literary mainstay for centuries. Not all vulnerable characters will fear for their lives the way Lianne does when she learns about Philip’s gun, but they still need to put food on the table or make a good impression at that interview or pass that exam. The character’s weakness or vulnerability can be anything, so long as the writer convinces us that it’s something we need to care about. For instance, we might not be naturally inclined to care very much about whether or not a woman is noticed by a man at a social gathering. But by using her absolute command of the craft of writing fiction to probe her characters’ motives and build dramatic urgency, Jane Austen makes us care very much about whether or not Mr. Darcy asks Elizabeth Bennet to dance. Characters don’t have to be sympathetic either for us to care what happens to them. They just have to be interesting, and perhaps have something at stake, something to lose. The criminal fears discovery. The liar fears the truth. The drunk fears the morning light. The bully fears retribution. The brutish, bigoted skinhead fears for his younger sister’s safety. A good writer will always find ways to make his readers care what happens to his characters, because he cares what happens to his characters, and if he cares enough he won’t have to work to make his readers care, it will simply happen.

What makes a character unforgettable? Unfortunately, that’s beyond the writer’s control and has everything to do with how the reader responds to the story on the page. All the writer can do, to the best of his or her ability, is create. The reader will decide if that creation deserves to be remembered.

Much like Charles Dickens, John Gardner (1933-1982) was a master at characterization. His books are crawling with lovable, infuriating, hilarious and frightening characters. He was also a teacher, and for guidance and instruction you can't do better than to read his books on writing, The Art of Fiction and On Becoming a Novelist. If you don't have time for those, start with the Paris Review interview.