When most people think of radio drama, they probably envision a family from the 1940’s gathered around a massive console radio listening intently to the latest adventures of The Lone Ranger, Little Orphan Annie, or Captain Midnight. Today, that behemoth of a device has been replaced by a pair of earbuds and a smartphone. Whether you prefer podcasts, downloads, or streaming, the popularity of pocket-sized technology has resulted in a renaissance of what is now known as audio drama. That’s good news for writers, since it provides one more outlet that’s hungry for good stories.

But most scriptwriters in the new millennium are accustomed to writing for visual media. So, how do you write a script that, simply put, doesn’t have any pictures? Laid out below are four guidelines that should get you started on your journey toward writing compelling, impactful audio drama.

1. Employ Sound Effects to Set the Scene

Sound effects are crucial in audio drama. They set the scene for the listener and create an environment appropriate to the action. For example, a classic radio western like Gunsmoke might feature a rough-and-tumble fight scene in Kitty’s saloon that would be alive with aural chaos: glass shattering, wood splintering, people yelling, gunshots ringing out. Thanks to the sound effects, listeners could easily picture the brawl in their imaginations and conclude that Dodge City is not for the faint of heart.

Sound effects are also essential to pacing. Gunsmoke was ingenious at using sound effects to create tension. Imagine a dialogue-free scene where Marshal Dillon cautiously searches for a gunfighter holed up in a stable. We hear the marshal’s boots crunch on the gravel. Crickets chirrup. Horses whinny. A dog barks in the distance. Suddenly, a rifle is cocked. Shots are fired. A body thumps to the ground, followed by a grim death rattle.

Marshal Dillon’s appeal for one of the onlookers to call Doc Adams tells us it wasn’t our hero who fell victim to some dangerous hombre. But until those words were spoken, it was the sound effects alone that told the story…and kept listeners glued to their radios.

2. Use Dialogue Effectively

Dialogue is an essential element of audio drama. It paints a picture for the listener and keeps the story moving forward. Without visuals, the audience is paying special attention to the way the dialogue sounds. Unless they’re at a reunion of English majors, people don’t usually engage in grammatically flawless discourse. So, keep it real. Don’t be afraid to use halting speech, inelegant syntax, awkward silences, incomplete sentences—pay attention to the way people talk in real life and then put that on the page.

Dialogue also has to describe what’s going on in your story. One of the scripts I worked on for the mid-2000s series The Twilight Zone Radio Dramas was an audio adaptation of “The Invaders,” a Richard Matheson thriller about a woman whose remote farmhouse is invaded by little creatures from outer space. Twilight Zone zealots will recall that the television episode had almost no dialogue. How to adapt such a beast for audio?

The producer and I agreed the best approach was to have more than one character being terrorized so that all the action could be described through their dialogue. We made them an older married couple; one of them going blind, the other on the brink of deafness. This ensured that all action in the drama was explained sufficiently as she described to him everything she saw, while he reported everything he heard. It was the perfect solution to give the story momentum, reveal both character’s affection for each other, and keep listeners engaged…all through dialogue.

3. Make Characters Distinct

Since you can’t see what the characters look like in an audio drama, their personalities must be revealed in other ways—often through dialect, word choice, or a unique way of speaking (as you can probably see, this category tends to overlap with the previous one).

The classic Dragnet series is a good example of how a radio drama can be enhanced by distinct characters. As Sergeant Joe Friday conducted his investigations, he had a formal, emotionless way of speaking. The individual he was interviewing, however, was usually some distraught victim, hostile suspect, or quirky witness. Their intensity always contrasted perfectly with Friday’s straightforward “just the facts, ma’am” stoicism, resulting in unique, easy-to-identify characterizations.

In “The Invaders” episode mentioned previously, I decided to make the elderly couple a cantankerous old twosome with divergent dispositions. He was a curmudgeon embittered by his increasing blindness. She was an optimist who could still match him quip for quip despite her continual loss of hearing. This made their characters distinct and kept the dialogue lively. The irascible yet loving nature of their relationship thus became a crucial part of the story as they fought off their attackers.

4. Keep the Number of Characters to a Minimum

In an audio drama, the audience is identifying the characters by their voices. Too many characters can be confusing. Opinions vary on the ideal number of characters for an audio drama; somewhere around six seems to be the magic number. But a general guideline is to keep the maximum number of characters in each scene to four.

In Dragnet, any given episode might have had seven or eight characters total, but most of them were introduced to us one by one as Sergeant Friday and his partner conducted their interviews. With no more than three people in a scene, the listener could focus on specific characters and their part of the story without getting overwhelmed.

One original Twilight Zone script I wrote, “There Goes the Neighborhood,” only had three characters total: a mild-mannered scientist, his beautiful but bigoted spouse, and a tender-hearted creature from another dimension who had a wry sense of humor (don’t they all?). By keeping the number of characters to a minimum, the writing was leaner and the drama was more focused and intimate—not to mention cheaper—than if it had featured a large cast.

To hear examples of the above guidelines in use, I recommend listening to audio dramas. Seek out shows from radio’s golden age like Gunsmoke, Dragnet, Escape, Suspense, and of course—the jewel in the crown—Orson Welles’ War of the Worlds. Watch an episode of the original Twilight Zone TV series and then listen to the audio adaptation to hear what techniques were used to tailor the story for the aural medium.

Lastly, BBC Radio is required listening. From the world’s longest-running radio soap opera (The Archers), to contemporary thrillers, to new adventures of Doctor Who, the BBC has long been renowned for its audio drama division. You can stream episodes of recently aired dramas via BBC Radio’s website. Their productions are showpieces of atmosphere, characterization, and storytelling—worthwhile goals to aim for as you embark on writing your audio drama.