The key to writing a good novel is to be consistent and disciplined. Set a writing schedule and stick to it. Do lots of research if needed for your topic. And read a lot of other novels to learn from different writing styles.
To write a novel well, you need to plan your story. Outline the main events, build believable characters with depth. Also, pay attention to the pacing - keep the story moving without rushing or dragging. And don't forget to revise and edit your work multiple times to polish it.