I wrote a post last year some time addressing the debate over Talent vs Work. (It's an old argument. Probably even older than Outline vs Pantsing or Character vs Plot.)
Now that I'm digging back into the submission game I've a bit more to add.
There are, in my opinion, three factors that determine whether or not a story sells.
1) The talent level of the writer. Whether talent is learned or innate, some writers are better than others. Just like some athletes run faster than others. I'm not saying this as a "You suck!" argument. Simply pointing out that there is a certain skill level that is required to achieve professional publication.
2) Luck. This boils down to hitting the right market with the right story on the right day while the editor is in the right mood. Unless you're consulting a ouija board or the spirits of your ancestors there is probably not much you can do about this aside from hit every possible market as often as possible with everything you've got.
3) Hard work. I've said before that hard work will trump talent every time. I still think that. In order to nail that sale you have to work hard. Work hard at writing. Work hard at editing. Work hard at submitting what you've written and edited.
Now. Of those three factors, which do you (and I) actually have any control over? (I'll bet you see where this is going.)
That's right: Hard Work. This is the only part of the magic formula for story sales that you can actually do anything about. Because talent is A) something you have or you don't and B) only gets better with practice. And luck... well, luck is what you make of it.
Too often we get caught up in the "Am I good enough?" trap. This is the mental block where we (and by "we" I really mean "I") start doubting whether what I write is any good at all. Do I have real talent? Will I ever be successful as a writer/author/scribbler on napkins? The answer, of course, is to work until you prove the talent is there.
Usually, once I get past the previous trap I get stuck in the "I must find the perfect market" trap. This is the one where I start spending all my time trying to find that one perfect market for a specific story. The one where it will sail through the slush pile and amaze and move the editor(s). Of course, the only cure for this mental glitch is to keep writing and submitting even when there doesn't seem to be a "perfect" market. Again, hard work is the answer.
Because talent is great and luck is amazing, but the nitty gritty of actually doing the work, well, that's tangible. And that's what's important.