I’m serious–do something awful to your characters.
Are you stressed, frustrated, irritated, or anything of the like? If so, take it out on your characters!
Take a happy character and break them. What does it take to wear your character down? Do they try to look on the bright side in the face of adversity? Or does it all build up quickly on them?
What does your character want? Ensure they will never have it. What would drastically improve your character’s life? Put it always just out of reach.
Who has the power to destroy your character? How do they use it? Do they succeed or fail? How does your character react to this other character trying to destroy them?
What is the one sentence that will cause your character to crack?
How many things does it take to ruin their life?
Make your character suffer.
“Why?” you may ask. “They’re my babies, my brain-children. I love them too much to cause them pain.”
That’s the kind of mentality that creates cop-out writing. If your characters have happy, sunshiney lives all the time, then how do they grow and change? I don’t want you to have static characters that are boring to read about. Even if they’re interesting, if they don’t change by the end of your piece of writing (or have an impending change), then I don’t care.
You have to do bad things to your characters. Even if you don’t include it in your final piece, let it flow through them, resonate in everything they do. If not, they’re just flat. Nobody is happy all the time with a perfect life, and it’s not realistic to pretend that your character can handle anything and everything. Hurt them. Let them know what pain is so they can learn and grow.
Write a short story in which every awful thing that could happen to a character happens. How long does it take to break them?