Desire

Writers must have a desire to write.  They must feel it in their bones.  A good writer will write regardless of if he or she is being paid or not.  The writer must seek out spare time to jot down a page, a paragraph, or even just a sentence.  Like any good marriage, desire will sometimes wane, but it should always return.  Moreover, a good writer will seek out ways to rekindle that desire so that the "marriage" of writer to writing is never forgotten.