1. Write what you love
2. If you're able - write the genre which is popular - this method is not always certain.
3. Home work. Research your characters - their careers, their medical history, even their clothing and cars. - Readers pick up on what is fact and what is fiction when it comes to certain topics.
4. If you think you are finished your manuscript, put it aside for a couple of weeks then go back over it. You will pick up mistakes, typos and rewrite paragraphs. Or change chapters. Look at it with fresh eyes.
5. Bad reviews are wasted words. Most of the bad one-or-two-star reviews are trolls copying and pasting a standard scripted paragraph to make you look bad. Did they even buy your book or read it? Never take a bad review to heart. If it is a real review - what are the positives to it? Or maybe use it to your advantage in your social media posts. Turn it around and make a negative to a positive and create new sales