Read a lot of great fiction works. That'll expose you to different writing styles and techniques. Also, practice writing regularly and get feedback from others.
Well, start by observing the world around you for inspiration. Pay attention to details and emotions. Then, experiment with different genres and storylines to expand your skills. Finally, be open to criticism and use it to improve.
To be a better fiction writer, you need to develop your creativity. Come up with unique ideas and characters. And don't forget to revise and polish your work to make it shine.