First, think of a unique concept or theme that interests you and your potential readers. Then, develop characters with distinct personalities and goals. Next, plan out a series of events and conflicts that these characters will face and overcome. Finally, make sure there's a clear beginning, middle, and end to the story.
To create a storyline for a comic book, begin with a spark of inspiration. It could be a real-life event, a dream, or something completely out of the blue. After that, flesh out your characters - give them backstories, motivations, and flaws. Plot out the major events and twists that will keep readers hooked. Also, consider the pacing - make sure there are both intense moments and quieter, character-building scenes.