Ignore generic advice; it can harm as much as help. The most useful advice will come from those who have actually read your writing and know your goals, strengths, and weaknesses. Seek critiques from authors you admire. It helps if you are willing to reciprocate.
People knock wish-fulfillment fantasies, but starting with a wish you'd like fulfilled and then building a story off of that is a great way to produce an idea you are passionate about.
Back up your work often, preferably after each session writing. Assume your computer will explode at any time. Don't delete anything. Text files are small, anyway, and you never know when you might want to recycle or revisit an old idea.