There are two ways you can describe details in your character’s world: passively or actively. Describing something straight-forwardly, telling only of its presence on the scene, is called a passive detail.
This is not to be confused with the passive voice, which means having an object with no subject.
A passive detail is dropped in, set like a knickknack on a mantle and left there to decorate the room. But the thing about a knickknack on a mantle is that it can go unnoticed. Passive details are okay, and some elements can be done this way. For example:
“On the street, there was the smell of diesel fumes.”
Or:
“Frogs croaked in the woods all night as I tried to sleep.
Or:
“The sun setting over the mountain streaked the clouds pink.”
These are good details, but they are just sitting there being sensory details. If you make things active, your prose carries more energy.
So how do you do it? By including it as part of the character’s activities, movement, existence, and interpretation of their setting, and ultimately by relating it to the plot action. Watch as I take each of the previous passive details and make them active:
As I walked uptown, the smell of diesel fumes made me gag.
Or :
As I walked to the job interview, the smell of diesel fumes were a cruel reminder of industry—so many people working, delivery things, buying. All with their money. And I had none. I needed this job.
Or:
I lay in the cabin’s rickety cot, listening to the frogs singing. It was an off-beat, out-of-time croaking harmony—funny evidence of nature’s randomness. I forgot all about Jimmy breaking up with me that day. Suddenly it seemed like just another event out of my control.
Whatever it may be. In each of these cases, we can say that a character did something in response to the sensory detail, the element in their environment. One coughed, one had some thoughts, and the last, a young woman, listened, then felt, then forgot—she had an important change in perspective.
Cool, right? Suddenly the set dressings are interacting with the characters. If you think about it, this is the way it goes for us during the drama of our lives. Our sensory perceptions are heightened and perhaps altered during important, impactful times, and they act on us and color our world. Things are noisy or busy. Active environments, like a stock market floor, might make us nervous, tense, or exuberant. Serene, pleasant-smelling environments, like a bakery, make us feel calm and secure—or maybe bored or homesick.
So, you’ve probably been told to use the five senses in your descriptions before. But ask yourself, what is the environment doing to my character? Describe how the sensory details fit into the scene and what mood they create as well as how they influence a character. To do this is to make sensory descriptions active and sometimes useful in moving your story forward. For example, now that they young lady in the cabin has forgotten about her heartache, we might find her entering the water-skiing competition or getting the hell back to the city. Whatever is—next scene, and she’s a changed woman!
Remember, plot is a sequence of events, and something has to trigger one event to the next. It usually isn’t going to be a single sensory detail that changes a life. But it might be.