Say you're writing a story from a certain person's POV, and you want to describe the main character without being awkward. Since the character's eyes are attached to their heads, they can hardly describe themselves, but there's a way around that - have the character look at themselves in a mirror, and describe what they see.
This is usually slipped into a Morning Routine sequence, or when the character catches themselves in the mirror abroad. As well as being used for descriptive purposes, it can effectively be used to reflect character - suppose this person hates her appearance and usually avoids mirrors, or else closes in to focus on the flaws (pimples, wrinkles, whatever); have her get a good look at herself (say, in a mirror at someone else's house) where she can't spend time obsessing over her flaws, or are unable to close the distance due to a crowd (so that she's forced to stand back and get a view she doesn't often see). It could also be used to show their vanity - reflection on how gorgeous they look, or how they were sure no-one has as stunning [body feature].
But be warned, dear Writer: this trope is looked down on in some circles, partly because it's seen as a cliché and partly because of the amount of amateur fiction that use it poorly. The most common abuses are using it as a lazy substitute for feeding the audience a description naturally over the course of the story, and incongruously describing the character's appearance in much greater detail than is used in the rest of the story, which is usually just another way to tell us how awesome your character is.
Often uses the syntax "[Character] looked in the mirror, and a [description of character] looked back."
- Done in the first chapter of Bait and Switch to describe viewpoint character Eleya.
"As always, my dark green eyes are drawn first to the two angry pink lines across my left cheek."
- Subverted in Tealove's Steamy Adventure. Tealove looks into the mirror, and there's a paragraph-long description of the face staring back at her. It finishes with: "In short, it looked nothing like her." (It turns out Pinkie Pie has found a way to appear inside this mirror—that's who Tealove is looking at.)
- James Bond
- Used rather neatly to show both Terisa's appearance and a large part of her characterisation in The Mirror of Her Dreams.
- In Harry Potter and the Goblet of Fire we get the following narrative after Harry wakes from his accidental Dream Spying on Voldemort:
Harry ran his fingers over the scar again. It was still painful. He turned on the lamp beside him, scrambled out of bed, crossed the room, opened his wardrobe, and peered into the mirror on the inside of the door. A skinny boy of fourteen looked back at him, his bright green eyes puzzled under his untidy black hair. He examined the lightning-bolt scar of his reflection more closely. It looked normal, but it was still stinging.
- Andre Norton used this technique in her novel Forerunner Foray:
She looked into the cruelly bright mirror, cruel because being so often used to check a disguising makeup, it revealed rather than softened every defect of complexion and feature. There was the real outward Ziantha. And with this hour and her great fatigue, that sight was a blow to any vanity.She was very thin and her skin was pallid. Her hair, from the warm steam of her bath, curled tightly to her head, no lock of it longer than one of her fingers. In color it was silver fair, though in daylight it would show a little darker. Her eyes were gray, so pale as to seem silver too. The mouth below was large, her lips with little curve, but a clear red. As for the rest — she scowled at the true Ziantha and shrugged on her night robe.
- R.L. Stine uses this technique to describe Garry in Why I'm Afraid of Bees.
- This is Bella's occasion for describing her own appearance in Twilight. She considers her appearance unremarkable, but the description she gives suggests good looks, similar to those of the author.
- She gets it again after she has become a vampire, only this time she does consider herself pretty.
- Parodied in The Glimpses of the Moon by Edmund Crispin.
Here he paused by the mirror, from which, not unexpectedly, his own face looked out at him. In the fifteen years since his last appearance, he seemed to have changed very little... At this rate, he felt, he might even live to see the day when novelists described their characters by some other device than that of manoeuvring them into examining themselves in mirrors.
- Used at length in Shadow of a Dark Queen to describe Erik von Darkmoor, complete with comments on his demeanor and public image.
- An unusual example occurs in More Than Human as it occurs six chapters into the book, not at the beginning.
- Done in Samael's Interlude in Anathema.
- Done by Taylor in the first chapter of Worm.
- Used in Altered Carbon when the narrator, a frequent body surfer, sees his new face in the mirror for the first time.
- Whateley Universe: Used at least once. Absinthe has her Curtains Match the Window revealed this way:
I [...] turn[ed] to look into the small bathroom mirror. The same girl with the green hair and beautiful emerald eyes stared back.
- This is strongly discouraged in How Not To Write A Novel under the title "What Color Am I?" (Where the character must be in front of a mirror to know what she looks like).
- Discussed a few times in the Writing Excuses podcast, where they discourage and occasionally mock the practice.
- Specifically criticized in the article Top 10 Storytelling Cliches That Need To Disappear Forever.