Sleep on your writing; take a walk over it; scrutinize it of a morning; review it of an afternoon; digest it after a meal; let it sleep in your drawer a twelvemonth; never venture a whisper about it to your friend, if he be an author especially. ~A. Bronson Alcott
I have counseled writers to learn to be patient, so much so in my online writers group that they must be sick of hearing me say it. But as you can see from the quote above written by a 19th century writer, there's merit to letting the stew simmer until it develops more flavor.
When a cook prepares a stew, she spends considerable time preparing all the ingredients that will go into it. She brings the meat, vegetables, herbs and liquid to a quick boil, then turns it down to simmer for two or three hours. The slow simmer cooks the ingredients to an edible stage and develops the flavor of the herbs and perhaps wine that is used. If she brought the pot to a boil, then quickly whisked it away to the table, her stew would not get rave reviews.
The stories, articles or poems you write are no different. Maybe a newbie writer works on a story all day, and by nightfall, they are happy with the finsihed result. They'll be eager to send it to a magazine editor and want to get it out the door before falling into bed, exhausted from the full day they've put into the story. But it's the wrong approach. Why?
For one thing, by the time that story is finished, the writer is tired and when she reads it to herself, she misses many small errors. If she sends it flying into cyberspace immediately to the inbox of an editor, she may have regrets the next day when she thinks of something she might have added, or a different approach.
She's better off writing the story, then setting it aside to simmer' for a couple days, maybe even longer. I guarantee that when she pulls it out and reads it several days, or weeks, later, she will see it with a new perspective. Mistakes will be more evident, weaknesses will jump out crying for a rewrite, and the strong parts will still be strong.
I mentioned newbie writers doing this, but old-timers do it, too. Maybe not quite as often, but they still do it when they're meeting a deadline or just in a hurry to have something finished to submit. Learn to have some patience. Let the first draft simmer awhile, then work on editing and revisions. I can almost promise that it will pay off.