P is for Peril
"Glory is the child of peril." -Tobias Smollett
Are your characters happy? Do they lead safe, contented lives? Do they never encounter danger?
If so, your story is in trouble.
Characters need to be put into peril from time to time, whether it is physical danger or psychological trauma (or even better, both!). Think about what they are most afraid of. Then make it happen. Do they have any phobias? Use them. We are all afraid of something, so your characters should be too. Make it impossible for the characters to turn back. Not bad enough? Put the person they love most in the world in peril. Have them make mistakes. Even better, have one of their mistakes endanger both them AND the person they love most in the world.
And don't forget the ticking clock.
For example, Joe has to save his sick daughter and wife from the kidnappers in 24 hours, or pay their ransom, or else. The kidnappers? Joe's mistress & her, um, brother. (They don't act like brother and sister, but that's for another blog post.) And the ransom? More money than Joe has. He might be able to get his hands on the money, but it will be illegal. By the way, they are being held in an abandoned coal mine. Did I mention that Joe is terrified of dark, cramped, dirty places? Or that the coal mine was abandoned because it kept collapsing, killing people? Or that his daughter has asthma...and left her inhaler behind?
Too much peril? You can always dial it down a bit by letting us see happier family moments, showing us why Joe fell for the diabolical kidnapper, or glimpses into what else is happening in their lives. But keep that peril alive.
If you don't, you're killing your story.