Because seriously, there is so much wrong with the slush pile.
Anyway. We're going to talk about Oath-breakers. Yeah, alright, I get nobody likes a liar, but that's not precisely what I mean. I mean oath-breakers in fiction. When you sit down and write, when you tell me a story, you're making a promise. Maybe it's not blood on the dotted line, but it's still a promise.
"Hey, you. This thing I'm telling/showing/sketching out for you, it'll have a beginning, a middle, and an end. It'll have a purpose as a story--maybe not a higher one, but whatevs, it'll still be a purpose--and it'll do all the things it's promising to do before you get to the end. We cool?"
Because when it doesn't do those things? There are whole lands of failure devoted to stories who fall down on those. The kind you need a sixteen-mule-team and a magical compass to navigate. Stay away from magical failure land, storytellers. Stay far far away.
It's not hard, just actually freaking finish your story. Finish it the way it should finish, after you've begun. Finish it like it's the last story you're ever going to tell, and it should hold up to the light of the ages, eligible for reprint in the Ancient Gazette when we're winging our way toward Andromeda Prime in a thousand year's time.