My advice is to read every day and write every day. I read for about an hour or more every single day. It helps to refine your vocabulary and study various writing styles. And writing every day helps me improve. The first thing I ever wrote that I hoped to publish was horrible! I shelved it for a bit, working on other things, and then went back to it. I cringed as I read it but I liked the story so I just did a lot of editing and reworking. Also, do NOT be afraid of rejections, bad reviews, or flames. They hurt for a minute but can sometimes help.