Well, start by giving your superhero a unique and relatable background. Maybe they grew up in a difficult situation that shaped their desire to help others.
To write a great superhero origin story, you need to focus on the character's motivation. What makes them want to become a hero? And create some villains or obstacles that test them. Also, don't forget to give them a flaw or weakness to make them more human-like.
First, think about what makes your superhero different. Maybe they have a special power or a traumatic event that drives them. Also, build up the world they come from to make it believable. Add some challenges they face early on to make their journey interesting.