Perform the Action.
Get up and act out the scenes, when possible. Sometimes the problem is that you’re not describing what a human body actually does in a given situation. If you’re describing someone climbing a ladder, then find a ladder. If it’s a fight scene, throw a few punches. Try out a few kicks. If possible, observe or take a martial arts class. How do people tend to fall: on their sides, on their hands? What sorts of exclamations do they make? Do they wipe sweat away, or do they ignore it? How does a body respond when a hand or foot makes contact?
Pick Up the Pace.
In writing action scenes, the pace must speed up, to match that of the scene. How do you do this? Keep descriptions of anything besides the action to a minimum. This isn’t the place for long descriptions of setting or character. Some writers use shorter, choppier sentences, or even incomplete sentences. And describe more than just what your protagonist sees. Study this example from John Le Carré’s The Spy Who Came in from the Cold for more clues on how to create fast-paced action scenes.
Keep Dialogue Short.
As with all of your fiction, dialogue is helpful for breaking up action scenes. However, when adrenaline is flowing, people don’t engage in lengthy discussions. To be realistic, keep dialogue short and snappy when writing action scenes. Looking again at The Spy Who Came in from the Cold, we find several examples.
Make Full Use of Verbs.
In the first draft, don’t worry about verbs: just get the action down. But in your revision, drag out the thesaurus. This is action, after all, the verbs are the most important words. They give your scene momentum. Take, for instance, this line from Tana French’s novel In the Woods: “Footsteps thumped behind me and Sweeney streaked past, running like a rugby player and already pulling out his handcuffs. He grabbed Rosalind by the shoulder, spun her around and slammed her against the wall.” “Thumped,” “streaked,” “spun,” “slammed”: they’re specific actions and they’re active verbs, full of energy and focus. Scenes like this are not the norm in life, so the verbs will not be everyday words, but nor should they call attention to themselves.
Learn from Other Writers.
As with all aspects of writing, you can learn a lot by studying the work of writers you admire. How do they get action across? What kinds of verbs do they use? What kind of descriptions? What gives these scenes a feeling of momentum? What kinds of sentences do they use in the faster scenes? Do they use more modifiers, or fewer? And while keeping plagiarism in mind, note what phrases they use in describing certain kinds of action. It can help guide you as you revise those scenes.