The best advice I can give is first, revise, revise, and revise again. I write long and then cut and cut and cut -- and I love the process of editing, of honing down. I have a photo I love to show my students of my now 20-year-old daughter when she was 1 sitting on a pile of manuscripts on my desk. On the left is the largest pile, which was the first draft of my second book, single-spaced. In the middle is a pile half the size and double spaced. On the right is the final draft, still double-spaced and still much smaller. I also warn; accept rejection as part of the process - so know you will get rejected, but refuse to get dejected. It takes time to get published but the best writing comes from passion and if your passionate no gatekeeper will be able to stop you from doing what you want to do.