When you have your character do one thing and think about something else, you create not only tension, but also character. This technique—often called “juggling”—refers to the way you move back and forth between action and thought to build immediacy, deepen character, and sustain narrative momentum.

For example, imagine your character is Loretta, a performer whose dangerous act involves juggling sharp, shiny hatchets with hard hickory handles. If she loses concentration, she could be badly hurt. Yet, while she tosses them into the air, her mind is elsewhere: she’s worrying about how to pay her father’s nursing bills. That worry triggers a memory from her childhood, when she collected cans of bacon grease for the war effort and her father told her, “You’re a little soldier.” All the while, we as readers are nervous about those tumbling hatchets. The tension lives in the gap between what she’s doing and what she’s thinking.

To make this work, you must first make readers feel the physical immediacy of the action itself. Choose an action you can describe authoritatively. Let’s consider another example: a man named Streater visits a childhood skating pond. If Streater is fulfilling an old wish by skating across a lake, you need to know enough about ice-skating—what natural lake ice looks, feels, and sounds like—to convey the sensations vividly.

That physical world must be rendered in specific detail and interwoven consistently throughout the scene. If you push Streater onto the ice in the first paragraph, then drift into his thoughts for several pages, and only return to the ice at the very end, the forward motion and immediacy evaporate. The momentum is lost. Interweaving thought and action keeps the story moving and makes the reader feel physically present. If the character is cold and wet, keep the reader cold and wet.

Going into a character’s mind offers enormous freedom. The human mind can cover an amazing amount of ground in seconds—vivid memories, images and sensations separated by years, voices from the past, fantasies of the future. A paragraph of thoughts spanning decades can occur in the time it takes to tie a shoelace. Out on the ice, Streater might recall an argument with his brother years ago or a recent puzzling conversation with a friend. He might not even know why these thoughts arise. But through them, we come to know Streater as well as he knows himself.

There are practical techniques to master when writing this way. One is the seamless shift between action and thought. It’s relatively easy to slide from an external action to an internal one. For instance:

Streater looked down at the old skates. The blue leather cracked and lined. The laces frayed. Damn. Nothing stayed the way it should. Not Elayne, not the house, nothing. He leaned down and pulled the laces to see if they had rotted. One snapped off right at the top eyelet.

The first sentence places us behind the character’s eyes. The next phrases describe what he sees. Then we slip into what he thinks, before moving back out to describe his action. In just a few lines, we learn of specific disappointments and a broader sense of loss—and we want to know more. You don’t need to write “he thought” every time, though it can be a useful transitional phrase. Avoid quotation marks for thought; they tend to distance the reader.

Give your character something interesting and active to do, something that requires both mental concentration and physical effort. If elderly, frail Maria is trying to dig a yellowjacket nest out of her tomato patch, readers will pay close attention. But tension isn’t only generated by danger. If Maria’s pride depends on caring for herself despite her age, even the struggle to thread an embroidery needle can create great suspense. If the action matters to the character, it will matter to the reader. Conversely, as with the juggler, tension also arises when a character should be concentrating, but is distracted by intrusive thoughts and memories.

This technique isn’t limited to any particular type of story or tone. It can serve serious or humorous intentions. If a surgeon is thinking about an argument with his Mercedes mechanic while performing a triple bypass, readers feel both a queasy unease and the sharp edge of satire.

Tension can also emerge from the trials of ordinary life—a character searching for a gift in a snobbish store, or trying to untangle a borrowed fishing reel. Readers respond positively when they recognize their own feelings in such moments. Fundamentally passive actions, like sunbathing, tend to fall flat. Even if sunbathing has a goal and potential pitfalls (will he burn? will the clouds roll in?), those worries rarely energize a story.

When you move skillfully between action and thought, your readers exist simultaneously inside and outside the character. That interplay—the dance between the external and the internal—is at the very heart of compelling fiction.