Writing is Rewriting
Excuse the language (or don't), but his words are true ... for me at least.
My first drafts are written quickly, and just for myself and my beta-reader. I tend to know my stories so well by the time I begin writing that I leave out chunks that readers will need; leading to fixed/rewritten/finished products that are longer than my first drafts. Other writers (like Stephen King) often go the other way, writing too much in first drafts, and ending with stories that are much shorter than the rough drafts initially were.
First drafts are messy incomplete and certainly lacking in polish, but they serve a number of important purposes.
I write my first drafts as fast as possible, on purpose. In the summer I write my novels over the course of a month, during either July or August; during the school year, I carve out chunks of time to write novellas and other, shorter, works during short bursts of frenzied typing.
Before my fingers get to work on the keyboard of my laptop, I will have been working on my plans for the story over the course of weeks or months ... mapping things out, and getting to know the characters and setting and story arc.
Once I begin typing, I try to let my knowledge of the story carry me along, and when things are working perfectly, am just listening to the characters tell me what happens.
When the rough draft is finished, my fingers are tired, my brain is fried, and I'm left with a mess of words ... exposition and dialogue jumbled together, with too much in some places and not enough in others.
The important thing is that I've told myself the story ... I can/will/do polish it later.
It sounds trite, but the worst novel sitting on your desk, printed and red-markered and post-it-ed to death, is a thousand times better than the novel that exists only in your dreams. Once you've written something - anything - you can set it aside for a bit, share it with a trusted reader, take look at it yourself, and then try to figure out what you need to do to the monstority in your hands to get it from where it is to where you want it to be ... what you want it to say/mean/evoke.
If you can write it, you can fix it and eventually make it great. If you're brave enough to write, and share, and look at, and edit your own stuff, then you can produce quality writing ... you cannot, however, skip the first, crappy, draft, in the process.
So write, even knowing that it may be, will be, horrible the first time ... write!
Rewriting your stuff is hard work at every step.
I am so happy with, and proud of, my first drafts, seeing my ideas enter the world for the first time is magical; then my beta-reader points out their shortfalls and deficiencies, and I wonder why I bothered. A bit of time to lick my psychic wounds, along with some honest reflection (and a read-through of the story) always ends up with me agreeing with the beta-reader. I then work, sometimes with her, sometimes on my own, to try and figure out how best to share the story and feelings in my head with readers.
I chop and prune and graft and add words/sections here and there throughout the story, and give it back to my reader to see if we're getting closer. I often have to 'fix' sections of my stories multiple times before it reads the way that I imagined it to my beta-reader and me.
It can be intensely frustrating, to feel your work, out there, just over the horizon, needing something to land it as a successful story, but that's the job.
"Writing" isn't just writing ... it's writing and sharing and reading and troubleshooting and rewriting and rereading and analyzing and rewriting and polishing and trimming and editing.
Mostly, writing is rewriting.