Self-forgiveness and Real-tenderness
I think self-forgiveness and what I call real-tenderness are closely connected, and are necessary interior skills that you must develop in order to create compelling characters.
I say self-forgiveness rather than just forgiveness because if and when you arrive at self-forgiveness you have already accepted and forgiven everything and everyone who warrants forgiveness. You have forgiven that relative who harmed you, that classmate that tortured you, you have forgiven Manson and Hitler, you have forgiven them all, and you are standing alone in a puddle, or ocean, of your own self-contempt. That is where self-forgiveness begins.
Anyone can feel tender about a kitten, but real-tenderness is a tenderness that you cultivate towards the contemptible. Can you feel tender about the father who comes home drunk after gambling away his paycheck and beats his wife and children? You must feel tender about all of your characters, and about half of your important characters should be easy to hate. But not for you. And you must also learn to live that way, because you can’t fake it in your writing.
Basically, the idea is to remove all judgment from these highly powerful emotional areas. These areas are self-illuminating, and are very bright; so bright that they flood out the flickering shadows created by judgment. Bathed in this light, you can reveal a character to your reader.