Focus the mind by learning to empty it
I was just flipping through a book titled Dojo Wisdom for Writers by Jennifer Lawler, and ran across this quote from another author named Miryam Williamson:
"With the ability to empty the mind comes the ability to focus it."
As the name of this book implies, Ms. Lawler applies lessons she's learned in the martial arts dojo to the craft of writing. The book contains 100 short sections with various pieces of wisdom, and I like to thumb through it some times, especially when I don't feel like writing. It has a lot of good tips for writers, including the quote regarding meditation shown above.