1. Write every day, even if it's a sentence, a plot idea, or hundreds of words, it does not make a difference, as long as you keep at it.
2. Keep reading; your favorite genre and something out of your comfort zone.
3. Never stop learning how to master your craft, listen to webinars and do those courses, there are so many authors offering that for free or at a low cost
4. Write what you want to write, yeah, write to market, DO THAT, but write what moves you, what made you start this journey in the first place.
5. Don't belittle your success, the fact that you wrote a book, is HUGE!