How on earth do you write fresh, vivid characters who haunt readers long after a book is finished? Especially when most of us are telling our own story over and over again from different perspectives (I seem to be all about finding a place to belong, for example.) I'd like to say I have a lock on vivid characters, but I suspect it's a lifetime's work-in-progress. Here are a few of the tools in my box. Try them. See if they fit your hand.
1. Know why. Why is a character where they are at the beginning of your story? Not just, 'hey, I'm working this job because I need the money.' That's the first layer. Excavate. Why is the money important? 'I mean to pay my way to college.' Sure, but why? 'So I can get a much better, more meaningful job.' You know what I'm going to do here, right? Sing along with me. Why? What does meaningful job mean and why is it so vital? 'Because we lived in poverty my entire childhood with my father and mother working two, sometimes three menial jobs apiece. They were never there. We were never safe from being evicted and uprooted AGAIN. I will not live like that. Never. Money is safety and I want it any way I can get it.' NOW we're getting somewhere. You know what this person believes. You know what this person's pain points are. You know exactly how and where conflict can come from, based on just a few questions.
Twisted as it is, rich characters come from a character's conscious or unconscious pain. Welcome to emotional/psychological archeology.
2. Hit 'em hard. Character arcs aren't supposed to be cakewalks. Can people change? Absolutely. We do it all the time. If we didn't, the species would have been snack-packs on the plains of Africa long, long ago. But that doesn't mean it's easy. That's why we have all the lovely motivational (or de-motivational) posters we do. You know. "When the pain of remaining the same is greater than the pain of change, we change." To that end, you have to gleefully stomp on their pain points time after time. Maybe the character above gets evicted? Or is denied entry to the college she's worked so hard to attend? if you know what's most important to your character (financial security for our character above) that is the thing that must be the lever that pries the character out of her old way of thinking/acting. Suppose she (or he) has to chose between True Love and The Big Score. Can't have both. Cue the angst. The character we know hasn't yet changed so she picks The Big Score, only to find that money may mean a swanky address and nice clothes, but it's lonely, cold, and unhappy. Oops. Suddenly that belief - money means security - is challenged. You have all the room in the world to decide what now. Does she go back to the lost love, begging for a second chance? Only to find that love married and living a happy, fulfilled life in a low-income housing project? Character has to process: How could they be happy? They have nothing except each other. Poor pathetic fools - man, I have everything I always wanted. Where's my happy??
Every 'ouch' resonates. Welcome to the business of forcing characters into choices that gut them - even when you're story is light and fluffy.
3. No win without sacrifice: When characters DO change - they meet their arc - somewhere along the line in that arc, someone or something dies. It can be literal death or metaphorical death, but something has to be given up. Our ambitious character is going to have to give up her view of her past - she might suddenly recall how much her parents adored one another and their kids. She might, slowly, come to give up her old belief that money means security - and by extension, happiness. Of course, having enough money to assure food and housing security absolutely impacts happiness, but once that's achieved, the character's needs shift. (Not because I'm being arbitrary here - it's the hierarchy of needs - once a baseline of security is established, humans rise up the pyramid of needs to be met.) In this story, you have a choice - if your character changes, she can give up her high powered job in favor of a fulfilling relationship and a job with a nonprofit - it doesn't pay a whole lot - but the work matters. Character fulfilled. If the character fails to make her changes, she watches all of her driven peers fall around her - they all five up their six figure jobs in favor of travel, or meaningful-to-them work, or relationships - and weirdly, they all seem so happy. Steeped in her unhappiness, but clinging to the assurance that if she just works harder, she'll get more money and THEN she'll be happy.
No win without sacrifice. If no win, the character IS the sacrifice.
Every character is an individual and no two will have the same answers to your 'why' questions. That, for me, is the starting point for unique characters. If I know the why behind them, I start hearing their voices. . . which may indicate a need for psychoactive medication. But hey. Writing's cheaper.