Well, you need a great story idea first. Then, focus on the characters and their designs. Sketch out the panels and think about the flow of the plot.
To create a manga or comic, start with a clear concept. Develop interesting characters with distinct personalities. Plan the story arc and think about the visual style. Also, practice your drawing skills regularly.
First off, for making a manga or comic, have a unique story in mind. Work on the character expressions and poses. Decide on the panel layout and use proper shading and coloring techniques. It takes a lot of patience and creativity!