After almost ten years, I've written 100 short stories, and had 67 of them published. That's not a bad track record. My attempts at writing at a longer length have not gone nearly as well. I've made two attempts at book-length work; neither worked out to my satisfaction.
My problem seems to be I can't outline anything that extensive without getting completely muddled. I now have a 12,000 word outline of a fantasy novel written by a close collaborator. I think I am going to take a break from short fiction for a few months and write this up.
My collaborator came up with an outline that has a scope and breadth that exceeds anything I ever came up with. I think it has great potential, and it is also for a high fantasy story. I first began writing short fiction for submission over the Labor Day weekend in 2002. It would be cool if I marked my tenth anniversary as a fiction writer by finally completing a well-plotted, entertaining book.
In the meantime I still have two stories slated for publication later this year, and a half dozen in various slush piles. I think I can take a break from the short fiction for a few months and work on this.