As someone experiencing a similar predicament to the writer Emma is detailing in her post--although I know I can still do a bit more to improve the two manuscripts looking for a home, and I'm not particularly frustrated either--the latest post on This Itch of Writing kind of interesting.
I'm not that analytical on the technical side of things, but try and pay attention to the mechanics of the art of writing, if that makes sense and doesn't sound too pretentious. The question of what work best suits a writer is at the crux of Emma's post. It's an interesting question. Maybe an easier one for writers like Aliya and me to answer, as we write so many short stories. Personally I was delighted with Overturned, the story we wrote together. So, what story or book do you feel is you, cooking on gas, all cylinders firing?