Here it all is in a handy-dandy cartoon by John Atkinson, who blogs at “Wrong Hands.” 
Quotable Words: Donald Murray on Writing
The writing teacher and Pulitzer Prize-winning journalist on just getting on with it…
“The longer I write, the more important I believe it is to write the first draft as fast as possible. In drafting, I push myself so I am at the edge of discomfort. . . Later, it will be time for consideration and reconsideration, slow, careful revision and editing. But on the first draft I have to achieve velocity, just as you do if you want the bike to balance.”
-–Donald M. Murray
A Few Reasonable Words 