Reincarnated as Ghostface in My Hero Academia

A reviewer made a good point about my fanfic that the story revolves to much on the mc and does have any world building. So I want to ask u the fans do I restart the fanfic or do I just add some world building for the other characters in the next chapter. And just to make it clear to is that this is my first time actually writing anything. So please give me criticism so I can make all my stories better.