When it comes to 'Rewrite the Stars' fanfiction, a great way to start is by focusing on the emotions of the characters. You could rewrite it from a different character's perspective. Say, if the original focused on the male lead's view, rewrite it from the female lead's. This can give a fresh take on the relationship and the story as a whole.
First, get familiar with basic drawing tools. Then, learn about character design and composition. Don't be afraid to make mistakes; it's all part of the learning process.
To make a comic book guide for beginners, start by studying some existing comics to get a sense of the format and style. Learn about different types of perspectives and how to use them effectively. And practice, practice, practice your drawing and writing skills!
Start with basic shapes and simple lines. Focus on proportions and poses. Practice sketching eyes, hair, and facial expressions a lot. That's a good start for beginners.