I'm still relatively new in the publishing world. Doing well in electronic publishing, and still struggling to get that one good NYC contract.
As the senior editor for a small press, I can say with 100% enthusiasm that right up there with learning the market on the Need-To-Know List, is Learn your craft.
Take the time to learn all you can about the art and science of structuring a novel/novella or short story. Everything from scene and sequel to the basics of proper grammar and punctuation.
Here are just a few links to get you started. It's a long process to learn it all. (Trust me, I'm still learning and have been writing for over ten years.) But out of every job/career I've had in my life (more jobs than careers) being a published author is the most rewarding.
I wish you all the luck in the world in your endeavors.