Personally I view writing as art, you don't have the masterpiece on the first brush stroke.
I do the following
1st draft - pretty much a brain dump, I write without regardless to grammar, subplots, and details so in the end it looks like this
Jack ran around the big vampire to snatch the grey keystone
The vampire falls dead from Jack's sister as she calmly remarks on Jack's lack of planning
2nd draft is plot, location details and character details
As the full moon rose behind Jack, he stared at the cyprt intentely. "This must be the place" he muttered shoving the map back into his pocket. "Damm I wished I remenbered to get the garlic. Oh well DartLing knows I am onto him and will move the keystone"
Jack dodge to avoid the crashing blow of the heavy stone as DartLing was on him faster than he could blink "Give me the stone human and I promise your death will be quick". DartLing was about to speak but the words would forever remain un-spoken as a razor sharp yew stake pieced his black heart.
"Thanks Sis, althought I had him" Julie snorted as she rolled DartLing over with her foot aiming her huge crossbow at the smoking corspe just to make sure. "Yea you had him like the time you tried to see the Macaw Cystral and forgot your wire cutters".
3rd draft - Grammar, spelling and flow
4rd draft - I give it to someone else to read and comment on it (not the whole thing just a few choice chapters)