/lit/ - Literature

How should I go about adding diversity into my writing?
Sorry if this has been asked before. I totally understand how important diversity is and I’m good at that with sexualities and genders but I don’t know what to do about different cultures and races. I don’t want to add in a black/Asian/ etc character as a main character that is basically white but with a different look bc I’ve heard that’s wrong but I don’t want to just have side characters as diversity because it doesn’t really count.