Even the very best and published writers think, write, rethink, correct, and write some more before arriving at a final draft. Check out the many drafts of Donald Hall's poem, Ox Cart Man! What a fabulous thing to show students and reinforce the idea that writing is a process that takes time and thought!
What's the most number of drafts you've taken a piece of writing through before it was ready to publish? Do you share your work (process) with students?