The story is that the pyramids were never really finished until the pharaoh died, and then they had to be finished in a hurry. The difference with a story is that if you die, nobody’s going to finish it for you. (Unless you’re already famous, but then this post isn’t for you.)
So you need to finish that story, because the perfect story doesn’t exist–ergo, it’s never finished, and it never gets subbed, and it never gets published. That’s why perfect writers never get published. Of course, the question then is: How do I know when it’s good enough? And as with so many of life’s questions, the answer is another question: How long is a piece of string?
Okay, that’s cheating. The answer is that you probably don’t know. You need someone with perspective to help you out. Preferably another writer, one whose life/job/happiness doesn’t depend on you. But happily, as you mature as a writer, you need less of this help, at least in the early draft stages. You learn to recognize what’s good and what’s not, especially if you have offered (and I can’t recommend this enough) to help some other writer hone his work. There’s no better way to see your own flaws than in someone else’s work. (It also does wonders for your diplomatic skills.)
And as you mature, you will recognize your limits. Maybe this isn’t your best work. (After all, there is only one “best work,” like there’s only One Ring.) But that’s okay. Your “good” stories may be good enough. The secret is to make them the best you can, but be prepared to let them go. Kind of like raising kids, but cheaper and with fewer temper tantrums (at least on their part). And by “good enough,” I don’t mean good enough to sell, but good enough that you’re not ashamed to let them out into the world.
Because like I said, they’re your kids. And they may not be perfect, but they’re yours, and it’s time you let everyone know how proud of them you are.