I guess the real question is, am I a "seat of the panser" or do I write following an outline. For me, I think the first few weeks of developing an idea should always be by the seat of your pants. Let the creativity flow, even if it doesn't make a lot of sense.
Don't let formats, or plot holes, or even spalling, stop you from writing. For me, writing is like turning on a water faucet. Sometimes the water is flowing like a gusher, and sometimes a trickle. In either case, the water is warm, hot, cold, or lukewarm. (I'm starting to like this analogy)
One of m family jokes is that the ONE member of the family who is a writer, can't spell his way out of a paper bag. I've never let tht bother me, or slow me down. I recall going to church and thanking God for Spell Check being a common option in Word Processors. This from a guy who was once hired as a technical writer. (No, they didn't like anything I wrote and I was fired after just a few months)
My advice is to go with what is flowing from your creative brain to the paper, through your fingers most likely. I read a book recently where the author said she'd gone through 30 re-writes. Try to pathom that for a second, a full novel, 30 times. How many times did she stare at the blank page and think: "What comes next?", she had 29 examples of what came next.
I once worked as the Head Chef of an Italian restaurant, we got ONE shot at each meal. I can't imagine turning to a customer and saying: "Don't worry, by the 30th time we'll get your chicken dish just right". Of course, before we even thought of putting something on the menu, we tried it many times... "What if we added a bit of that sauce from the steak dish...", and so on. We re-wrote that chicken dish a hundred times, before it was published, I mean, served to the very hungry public.
But I remember the first time I got on a bicycle... rode it like a pro, I was 9 and I was trying to find out how to sign up for the Tour De France. Then I fell off the bike, cried, didn't get back on it for a few days. But then I rode to the corner, then around the block, and fell, cried etc etc. But I did get back on, and wow I am please to report that later that year, I rode the bike both TO and FROM school.
I still cry when I fall, you can too.
Is there a book to read that will tell you exactly how to write a book, 100's. That's confusing. If there's one great way, why are there so many books on the topic? Should be... one. But that's the thing, there is ONE WAY to write a book, the way that works for you. Every time you sit down to write, you can say to yourself, I'm doing this the right way.
Its not a matter of how many words, or how long you sit, it's a matter of letting the creativity flow from the place in your head where the idea started.
How many times have I heard that an object in motion will tend to stay in motion, where a stationary object wll tend to stay stationary. (I read these posts over and over before publishing, so I guess I've read that a few more times) Its a rhetorical question, may many times. The flow of your story, from brain to fingers, is the object in motion. Stay in motion as long as the water is flowing. Don't stop the flow to check the spelling, to make sure that you didn't just make a HUGE plot hole, to make dinner. A really bad movie script once said: "A Jedi feels the force flow through him...". Be a writer, not that being Jedi is a bad thing, but right now it doesn't pay as well. (I know, I checked)
Now... back to my own flow...