Ok. One of my old ideas was about teens, whose parents are superheroes. And those teens go to a superhero high school. Sounds simple, huh? Well. It is. So, why I didn’t write it? It’s because the main story idea was very much like Rocketjump’s Video Game High School. (BTW, one of the most awesome web series of all time.) But I don’t like stealing ideas. I hate it when people do this! So… back to topic. How do I change the story of my idea? And how do I get ideas for each episode?
There are currently 7.5 billion other people on the planet, and that's not including all those who have died in the course of human history. If you try to do something that nobody has ever done before in search of "originality" you will: 1) drive yourself mad. and 2) fail, or possibly 3) Succeed by making something utterly bizarre and abstract that lacks any coherent plotline... only to discover that bizarre and abstract has also been done.
Superheros having a family is not a new idea. However, that doesn't mean it's not "original" to you. The issue is with how you define "originality."
The root word of "originality" is "origin," and an "original" idea is one that originated with YOU. That's all.
As a child I invented the concept of a shopping mall, where you could go to one place and get every kind of store at once. Yes, it already existed, but I didn't know that, and it WAS a good idea. Just because someone else has also, independently, come up with a similar idea doesn't make it any less "original." And unlike shopping malls, which can only be set up in so many ways, if you proceed with this project, the odds of you accidentally recreating someone else's work in its entirety are basically nil.
Heck, this explanation of originality isn't my own idea. I learned this bit of wisdom from an essay by Tommy Wonder.
Have you ever participated in an exercise where a bunch of people write from the same prompt? The fascinating thing about these exercises is that even when everyone shares a starting point, each writer immediately takes the story in a completely different direction, following the thread through the maze of their own mind.
Write good stories. If you're aware of similar projects and fear unintentional copying, avoid reading/watching those similar items until after your project is complete. As long as the stories come from you, they will be original. It will happen without even trying, so just enjoy yourself.