When writing a novel, how can a character be developed well, but QUICKLY?

“Hang on, are they playing ping-pong?”

“Claire! Why are you still up?”

Create a context between this character and other characters.

What is some information about unprotected sex and pregnancy?

“Number one, it’s not porn, it’s ecchi, and number two, why would I waste a perfectly good Saturday doing anything else?” Claire pulled at her tea and sighed. “The only thing that could make this day better is if you'd come home with some cute boy, so that after you kicked him out tomorrow I could live vicariously through you.”

Doing something they enjoy, that expresses their personality, and that is in some way unusual or noteworthy;

“Exactly.”

Is Matt Gaetz qualified to be Attorney General of the United States?

May yelped. “Hey! Your feet are cold!”

“Well, maybe if you didn’t spend all day reading—” May prodded the book with its garishly-coloured cover with her foot. “Bizarre comic book porn…”

“Yep!” Claire chirped. “There’s this schoolboy, see, and he’s homeless, so he lives in this boarding house that used to be a hot springs bathhouse, which is cheap because it’s haunted, so he decides—”

IPOs That Launched Like Rockets — and Those That Flew Straight Into a Wall - PYMNTS.com

“I’m just a fan of your catch and release program.”

“Well, maybe if you’d wear more clothes, they wouldn’t feel so cold. Hussy!”

“Why is that always your first suggestion? I do not need some tea. It’s three o’clock in the morning! If I have tea, I’ll never get to sleep.”

What is the reason behind some people wearing trunks instead of speedos when swimming in pools?

“Yuuna and the Haunted Hot Springs!” Claire turned the book around.

“May! You’re home late! Early, I mean. Well, I mean, it’s early in the morning, but you’re home before I expected. Er, after. Before?”

“I’m serious!” Claire said. “It’s staring straight at me.” She let the curtain fall. “Weird.”

I see ugly guys dating gorgeous, "hot" women all the time. I, too, am not very attractive but I'm not doing well with the ladies. What's their secret?

“Cute girls?”

“Fine.” May collapsed into the warm spot Claire had just vacated.

“It’s not looking at you.”

Why can't I lose weight?

“Thanks. You’re looking pretty ratty yourself. Have you been in that bathrobe all day?”

“I don’t know. Partying. Going to a pub. Anything besides sitting on the couch reading…” She squinted. “What the hell are you reading?”

“Tart!”

What baseball stories from the early days of the sport seem too bizarre to be true?

“You don’t need a cat. You can’t take care of a cat. You can’t take care of a ficus.” Claire flopped on the other side of the sofa and wriggled her feet beneath May.

“Yes way. It’s washing itself under the street light. Uh-oh, I think it spotted me. It knows I’m watching it. I swear it’s looking at me.”

“Claire, I—”

Why am I totally different than others? Why do I have a problem with my basic knowledge about society and reality? Why am I dumb and stupid?

“Exactly.”

In the kitchen, Claire set out a battered pair of mugs: May’s black, with “PEBKAC: Problem Exists Between Keyboard and Chair” in white letters; Claire’s white, with “This must be Thursday. I never could get the hang of Thursdays” in dark blue. She carried both mugs into the living room. “A moggie followed you home? Is this some weird Internet slang I’m not current on?”

Claire, one of May’s three flatmates, former university roommate, and best friend in all the world, shrugged expansively. “It’s a Saturday night. What else would I be doing?”

Why are white women not interested in dating Asian men? Are they not attractive to you at all?

“I know! That’s why I’m putting them under you!”

“But they’re cold!”

“You need some tea!”

What do dreams about dead people mean?

“I need to do laundry.”

“I try not to, but thank you for reminding me. I know I don’t need a cat. I don’t want a cat. What would I do with a cat?”

“No way.”

Do you think your landlord should have a key to your room?

“So you didn’t meet any cute boys at the club tonight?” Claire called as she bustled about the small kitchen.

“Nary a cute boy in sight.”

Do that and you can ground your characters quite quickly.

Essentially, what you do is show the character:

“It’s a cat. All cats are weird.” May sipped from her mug, inhaling the warmth. She closed her eyes. The room spun. She opened them again. “Ugh. I think I drank too much.”

They both burst out laughing. “I’m right, though,” Claire went on.

May pushed Claire’s feet away. Claire rose to peer out the window. “Huh. It’s still there.”

Here’s how we presented the character Claire when she was introduced, which the agent particularly singled out:

“Damn straight. So get to it! This time next week, I want to hear some moans coming through that wall.”

“From the look of you, if you try to sleep now, you’ll spend the next three hours hanging onto your bed trying to stop the world spinning. Since you’re not going to sleep anyway, you might as well keep me company.”

“Perv.”

The agent had only one bad thing to say (the synopsis was crap; writing synopses is hard!), but praised the characterization and particularly how well we introduced a character’s personality quickly.

“Nope, I mean a cat followed me home. A black cat, to be exact. All the way from the club. Probably still out there, for all I know.”

May studied the black and white comic panels. “Oh, my. She looks…anatomically implausible. What is she doing to that poor man? Wait, are those cat ears?”

“They are! He broke the rules of the boarding house by petting this character while she was in cat form, so they invoke the ancient rules of single combat via ping-pong, and—”

After Eunice and I finished London Under Veil, I entered the first chapter in a contest at a convention where you could submit something and have it critiqued by a professional book agent.

Claire sat back down, legs tucked elegantly beneath her. “You are looking a bit sloppy,” she said, inspecting May through narrowed eyes.

“You know what? Never mind,” May said. “I am way, way too drunk to be having this conversation.”

“None of those either. Look upon the wasteland that is my sex life, and see that it is barren. Naught but a moggie followed me home.”

“No, about the cat. You don’t need a cat. You remember what happened to your spider plant, right?”

“About wearing more clothes? How am I supposed to catch any fish if I don’t show off the bait?”

“I’ll put the kettle on.”

“I’m glad my sex life is so entertaining.”

Engaging in conversation that also shows something about their intelligence, personality, wit (or lack thereof); and