My instructor for many years was Ninja Grandmaster Robert Law. He is a darkly complex and dangerous man. His teachings left an indelible impression on me and I will be indebted to him always. He taught me all that I needed to know about writing.
One day, he asked me to clench my hands into fists and stand just close enough to a wall so that my fists touched it.
"Turn your head to the right and then turn it back to face the wall," he said. "What do you see?"
"The wall," I said.
"Not that, you dumb-ass," he said. "Look at your fists."
They were a quarter inch from the wall.
"Now turn your head to the left and back. Now what do you see?"
"They're touching the wall."
"You figured out why?"
"No," I said.
"When you do, you'll know a lot more about the way a ninja thinks than you do now."
Here's the short form: understanding body dynamics is the key to ninja techniques.
What does that mean for writers?
It means that a writer has to understand how their own mind works in order to write well. That is the reason for years I've said a writer should first understand the way he thinks, imagines and feels because this knowledge is critical to good writing. Deal with the creator first and the creation will follow.
The Witch's Brew is to concentrate only on the story and ignore the writer.
It is the writer, after all, who produces the story.
Know what excites you, what makes you cry, what makes you laugh, what makes you angry. Understand your need for justice and your need for recognition. What drives you, what slows you down.
If you understand these things about yourself, you will have a compelling narrative voice.