I don't pretend to know the trick to being published. In fact, I once read there are just three things to know to get published, unfortunately no one knows what the three things are. I don't know about that, but I do know one thing. Patience is a requirement. Of course everyone talks about persistence, but you don't hear about patience often.
Here's my example. GGE is working on two properties right now. "The Forsaken" and "Insurrection" (both working titles). Both of these are substantially finished. Note, I said substantially finished. Not finished. I was very tempted today to send the works off with some query letters. Finally, my better nature took hold of me and I held off. The works should not (and will not) be sent out to anyone until they are more than substantially finished. They need to be finished and polished and polished and polished.
I am always once to seek out a metaphor...here is my metaphor: I am currently working on restoring an antique armoire from near-destruction to its original grandeur (another hobby of mine). Anyway, the armoire is re-assembled, but is not yet stained or covered in a coat of polyurethane. It needs sanding with rough sandpaper and then sanding again with finer sandpaper and then sanding again with even finer sandpaper all so that when I finally do stain the armoire and cover it in poyurethane it will look as good (or better) than it did a hundred years ago. If my patience ran out and I stained it right now, it would still look good, but it would not look perfect. The same is true for a story and my odds of selling a story on behalf of GGE go up considerably when it is perfect.
Our stories will be in competition with hundreds of other stories received by agents and editors. I hope to only compete with the other polished stories, not the ones that are just "good enough".