I take as much time editing as writing, usually 10 drafts minimum.
Here's what another fellow says:
"I work like a pack mule, but it's my own choice. I'm like a galley slave who's chained for life to his oar but who loves the oar. Everything about it. I go over each sentence, time and again. I start cutting all the words it can do without. You have to keep your eye on the job because words are very sly, the rubbishy ones go into hiding and you have to dig them out--repetitions, synonyms, things that simply don't mean anything. I go over every image, metaphor, comparison, to see if they are fresh and accurate. If you can't find the right adjective for a noun, leave it alone. Let the noun stand by itself. A comparison must be as accurate as a slide rule, and as natural as the smell of fennel. I take out all the participles and adverbs I can...Adverbs are lighter. They can even lend you wings in a way, but too many of them make the language spineless. A noun needs only one adjective, the choicest. Only a genius can afford two adjectives to one noun. Line is an important in prose as in an engraving. It has to be clear and hard. But the most important thing of all is not to kill the story by working on it. Or else all your labor has been in vain. It's like walking a tight-rope. Well, there it is. We ought all to take an oath not to mess up our job.--Isaac Babel.