Thinking & writing
If you can think, you can write. That's always what I stressed to my writing classes at the community college, where mostly single mothers attended my remedial writing classes as they prepared for their first jobs.
No matter a writer's training or experience, thinking is the first step. We sit down at a computer and peck before we've even thought through a matter, chiding ourselves because it's not Fitzgerald.
Yet there is the very real challenge of putting thoughts into words. No matter how carefully thought out, however, plot cannot live without the fragile word body it must inhabit.