I try to let my stories off the leash in the drafting stage. It's one of the reasons why I work hard to banish my internal editor and get the words down quickly. But my natural tendencies do not go toward exploring extreme differences. Luckily, I have found that it's relatively easy to deliberately explore contrasts when I do my revisions. Why does this make a difference?
Think of a target. You'll imagine concentric circles of white and black (or possibly the color red). If you make the circles white and pale yellow or green and blue, the image is less riveting and finding the bull's-eye becomes more of a problem.
All other things being equal, a duet between a man and a woman is more compelling than between two men or two women. A friendship between a tall person and a short person (Mutt and Jeff) attracts more attention than a pair with comparable heights. Part of the art of cooking is combining distinctly different flavors. Each of these is compelling because we're built to notice and engage with contrasts.
So one way to add interest to your story is to emphasize differences. Let's explore five ways that you can enhance contrast and draw your readers and audiences in.
Physical diversity – Gender, size, ethnicity, dress, grooming, deformity, and beauty are just some of the immediate and accessible aspects of characters that can be presented to readers and audiences. The diversity of the crew on the Starship Enterprise was immediately apparent to viewers (and, to some, shocking in its day).
Defy expectations — If the appearances of characters don't line up with people's preconceived notions (the more), this creates surprises that make people want to know more. In Legally Blonde, the main character goes against the "dumb blonde" convention by being highly intelligent. In Crocodile Dundee, the outback adventurer outsmarts the city slickers.
Personalities – The classic here is the Odd Couple, which pits a slob against the neatnik when they are forced to live together. But there are plenty of other cases where people who plan are matched with those who improvise or straight arrows are matched with crooks. The variations in perspectives, values, and approaches to problem solving can be mined in ways that illuminate and amplify theme. This is especially true when the differences are pushed to the limits. One way to explore this is to create characters who are exact opposites based on personality testing, such as Myers-Briggs.
Impossible tasks – Imagine if the protagonist in Rocky had been the latest Olympic gold medal winning heavyweight boxer. Would the movie have been as interesting? Instead, he's a failed boxer who has lost his spot at the gym and makes his living as a leg breaker, someone sent to intimidate people who owe money. Luke Skywalker is not yet a Jedi. He's a farm boy. And he has to take on the Empire. While you have to stay within the bounds of believability (Apollo Creed does not take on a 12-year-old girl), giving the external goal of the story to an unlikely person creates curiosity and, because we want to root for underdogs, empathy.
Knowledge – Irony also provides an interesting contrast. It can make readers and audiences deliciously uncomfortable when they know more than the characters do. In a horror story, audiences worry when a character decides to go down
the hallway or enter a room where the monster, serial killer, or demon
is waiting. Hitchcock famously spoke about how excruciating a scene becomes when characters have an everyday chat in the presence of a ticking time bomb.
Usually, writers have the good sense to include conflict and tension in most scenes. They make sure dialogue is distinct enough so that a listener or reader, without cues, would know who is speaking. But, many stories squander opportunities to enhance differences. Either planning or in revision, looking closely for opportunities to increase contrast in characters, situations, objectives, settings, expectations, social norms, values, and more can raise better questions and create deeper emotional experiences.