Read a variety of genres
Any writer should know that one of the best ways to improve your craft is by reading. Read what you love. Read in your genre. Read the best of the best in your genre. But don’t stop there. Explore other genres as well. Most people write in multiple genres. For example, if you are a suspense writer, chances are that somewhere along the way one of your characters is going to have a love interest. Ah, there’s a little bit of romance. Or maybe your setting is in the Old West, a touch of western. Or suppose you’re dealing with a murder, could you be writing a bit of mystery?
Cross-genre reading will make you a more well-rounded writer and expose you to different writing styles, a variety of voices, and maybe give you a great idea for a story line that combines genres and themes.
Read much, read often. Your writing will thank you (and so will your readers).