Introducing characters is an art in itself.
I believe that a character should be described once, in a memorable and vivid way, and as early as the narrative allows. If you’ve done your job well, the reader develops an internal image, and unless it’s absolutely pertinent to the story, this should not be altered, tampered with, or even mentioned again (or it can pull the reader out of the story).
My approach is to introduce each character in a few lines, or preferably a single sentence, in a way that really cements the character in the reader’s mind. One of my writing buddies called this a Pen Portrait.
A Pen Portrait is a mini biography or a brief written description of a person or place. It’s a snapshot of who that character is, and what is distinctive about them. It’s succinct and pithy.
Here are some examples:
“They were unhappy Poms whose house smelled of boiled cabbage. George, the father, had very long feet. He wore socks and plastic sandals.” ~ Tim Winton
“Tight shorts and thin chest, he has the look of a whippet.” ~ Tim Winton
“She was pretty enough. Dominant upper lip, smallish nose, tanned skin with crow’s feet from the sun. And the stare of a cattle dog. Daunting.” ~ Tim Winton
“Ulyatt was fat and pink, cornsilk hair, tuber nose. He didn’t offer a hand, sat down.” ~ Peter Temple
“She was new on the job, Canadian, a mannish young woman, no make-up, tanned, crew cut.” ~ Peter Temple
Especially for minor characters, it’s important to make them real and authentic, and not just a prop in the scenery. Yet, it’s equally important not to waste too much time describing them, or you over-emphasise their significance.
The usual technique for this is to give them a quirk, such as a distinctive squint or a peg-leg, but you do your characters greater justice if you generate an immediate sense that we know exactly who this person is.
In modern literature, you have the benefit that most readers are saturated with all sorts of visual media (TV, movies, web), so we have a visual library at our disposal. Use this to your advantage. Take a piece of clothing, a hair style, or a facial feature and conjure up an image in the reader’s mind of someone they’ve met or seen on the TV. Use the idea of stereotypes without resorting to them. Hint at them, without actually ever stating them.
Here are two examples of pen portraits from my own work:
“Henna Pavarti is Bollywood beautiful. Petite, dusky caramel skin, spill of dark curls, large melting eyes.”
“Dumpy from too much junk food, but pretty in an overripe way, with dark hair savagely cut into a blunt fringe. She’s dressed as usual in a bargain-bin tracksuit, and scuffed sheepskin boots.”
Introduce a major or minor character in 30 words or less. If your style is more verbose, and less clipped and fragmented, I still advise you to stick to the 30 word limit. You can always add words later to match your voice, but the word limit will force you to focus on the key traits of your character.
Additionally, this works best when you also reveal something about your Point of View (POV) character’s values and aesthetics. Choose words that have an emotional bias, that are judgemental, critical, or loaded, or that hint at your character’s emotional state. If the POV character is happy, they might have an optimistic and complimentary impression of the new character, if they’re angry, they might be particularly harsh in their description.