I know you'd probably expect me to say something here about use of language or sounds, or maybe a mastery of grammar, or something literary like that, but as much as those help me as a writer, I think there's something that helps me so much more.
I like people, and I make friends easily. Those friends can be editors, fellow writers, publishers, readers, people who hate to read, whatever, but that skill has allowed me to build a personal network that had enabled me to get my stories into places I never would had I tried to operate as a Lone Ranger in my darkened room sending out blind queries.
I've said it before, and I'll say it again here. There are five key skills a writer must master to be successful: Networking, Time Management, Networking, Self-Editing, and Networking.