Would you rather be told your eyes are hazel or have them described as "the sherry in the glass, that the guest leaves”?
From that line, we could conclude the narrator or character is fairly wealthy: they drink sherry; they perhaps follow daily rituals, such as having an aperitif or digestif; they entertain in their home. (Or we might know that the sherry eyes belong to Emily Dickinson, but I digress.)
What matters is that description breathes life into characters.
Don’t rely solely on physical attributes.
He had a big nose. Is the nose big because it is broad, bulbous, hooked, or long? The definition of “big” is rather open to personal interpretation. Does it commandeer the face or flow seamlessly with other prominent features? Is the big nose indicative of a snitch, a chef, a snob, a sleuth? A basic description isn’t enough to round out the character. Use adjectives to create a vivid picture for your reader.
Speaking of vivid images, avoid bulging muscles, sad cow eyes, quivering members, and blonde bouncy curls. Keep your wording accurate and sensory. Show me a small child’s eyes hectic with fever and her lank, ropey curls plastered to her cheeks instead of telling me the kid was sick as a dog or under the weather.
Use description to create an impression.
Good characters are multifaceted, but sometimes one physical characteristic or a single article of clothing can say more about who they are than a dozen descriptions. Are the hands with their knobbed joints and thickened skin always busy at a task? If so, maybe they belong to an older character with a hard past whose work ethic is deeply engrained.
Setting and circumstance can also reveal or develop character.
One way to develop a character is to stick them in an uncomfortable or unusual situation. For example, does a bright young university student from a blue-collar background find himself at an awards dinner with peers, faculty, and more forks than he typically uses in a week? This is a great opportunity to show how he acts when he eats, how he responds when directly addressed by the dean, and what he thinks when the sexy tennis captain gives him her famous slow smile.
Air the dirty laundry.
Highlight a character’s backstory through techniques such as flashbacks, dialogue, memories, or foreshadowing to provide valuable insight. In One Hundred Years of Solitude, Gabriel García Márquez used flashback to give the world one of the most famous opening lines in literature: “Many years later, as he faced the firing squad, Colonel Aureliano Buendía was to remember that distant afternoon when his father took him to discover ice.” We wonder Buendía’s age, why he is facing execution, and why the memory of ice is so integral to his consciousness.
Show the goods.
If you don’t know Archie Goodwin and Nero Wolfe, you should. Read one of Rex Stout’s classic detective procedurals and you’ll learn how the most obscure or innocuous object can be a murder weapon or clue to the crime. When Archie saunters into a suspect’s home, everything from the cigars smoked to the socks in the drawer show us something about the suspect. A person’s belongings reveal much about them.
Verbs, take 1!
Set your character in motion. Rather than have a father reading the paper, show how he reads the paper. Does he lick his thumb to turn the page? Does he frown at the stocks or laugh at the comics? When your character peruses the job sections, is she scrawling circles around the ads or neatly placing a star beside them? These actions reveal the character’s motives, needs, and personality.
Verbs, take 2!
Verbs can also be used for physical description. For example, a sloping brow, the skirt that swished across the floor, bangs that fall across eyes, the broom that sweeps angrily…these illustrations give a portrait of the character, and you can build on these images to flesh out a scene or personality.
Verbs, take 3!
Sometimes, actions reveal more than words. Does the new mother jump up at the first cry of her baby or does she stay slumped in the chair? Do the clouds darken as the priest performs the last rites? What song is on the radio as the lovers confront one another about a betrayal? What hour is the clock chiming when the beleaguered employee rises from her desk, letter of resignation in hand? Does the protagonist light another cigarette before answering the telephone? Don’t just tell your reader what is happening. Show them.
What lies beneath.
Thoughts and existential crises present the clearest view of a character. Susan Fromberg Schaeffer gives us Agnes in The Madness of a Seduced Woman. Agnes’ inner world changes with the seasons: In winter, longing for her first sexual encounter, she observes the snow-covered hills mimic “the curves of a woman’s body;” after an unwanted pregnancy and dangerous abortion, in autumn that same scenery is “the earth’s skeleton shedding its unnecessary flesh.” Imagery like this can tell the underlying story.
Maintain the reader’s dream
Your readers want to be part of the dream you have for your story. Once in, they want to stay in that dream by falling in love with or despising the characters you’ve brought to life for them through descriptions, setting, circumstances, and imagery.