Just as you need your readers to see what your characters see, you also need them to hear what they hear as well. I’m not talking about dialog here.
Think about your scene. Where does it take place? Is there loud music? Are there crowds of people talking? If they are inside, is there the hum of machinery? Or perhaps, if your characters are out of doors, they hear birds singing, bees buzzing, water falling off a cliff.
We don’t just hear the sound of our own voices. We hear the wind. We hear the rain. We hear traffic on the main roadways. We hear all that and your characters should as well. Determine where the action takes place and let your readers hear the ambient sound. Unless you have a deaf character, there should be sounds around them.
I do guided meditations. One I heard not long ago, could help in this situation. It’s quite simple. The guide tells you to sit in a comfortable position, and listen to the sounds in the room and those outside of the room. Try that for about five minutes. Of course, you can sit there longer and drink in the sounds. Or you can just sit for a moment or two. The point is to just sit and listen to the sounds around you. How noisy the world can be, might surprise you.
Identify the sounds you hear. List them, either in your head or some tangible form. Know what they are. Then describe them. Is someone playing a radio in another room? Describe the music. You don’t have to recreate the words, just the impressions the sound gives you. Maybe someone is doing laundry or watching TV. Give a hint to what your characters hear as they move through the scene.
Dialog is obvious, but do the characters have to raise their voices to hear each other over the rain pounding on the roof? Or are they speaking in whispers because it’s so quiet and they don’t want to draw attention to themselves. What is going on in the scene? Does it have a sound you can describe? If so, describe it.
A good trick is to list the sounds things should make before you begin writing. Then add a word, phrase, or sentence that lets the reader know that those sounds are present in the scene. Sound can help you anchor your action in realism. Sound can help your readers immerse themselves in the scene. Give them something to listen to. Whether it’s music or just the sound of your character’s breath as it struggles to run away from the villain.
The sound of machinery can be relevant to a scene as well. A door creaks open. An elevator moans to the next floor. A car engine sputters to life. A jet screams overhead. A waterfall thunders into the pool below. It doesn’t matter what the sound is, if it should be there, put it there. You don’t need to go heavy on describing every little sound. Just hint at it, your readers will take it from there.