Realistic Fiction Situation

I have a situation. A realistic fiction situation. 

Yesterday, a student asked me where the Meg Cabot books were. I explained that she writes all kinds of books, but the only types of books of hers we had in the classroom library were realistic fiction (namely The Princess Diaries series, which my students love as much as I did when I was their age). 

She walked toward the realistic fiction section and stared at it, daunted. That's because the realistic fiction section looks like this: 

When I first arrived in this classroom, the books were separated into odd categories--"Boy Books", "Girl Books", "Kids on the Street", "Immigration Stories", "Friendship Stories", "Tough Subjects but Worth It". I didn't like this categorization system because I never refer to books in such a way. I refer to books by their proper genre and sub-genre name, and I wanted to teach my students to do so as well. Plus, I really disliked the judgement that surrounded some of the categories.

I also loathe the idea of a book being a "Boy Book" or a "Girl Book". My method for dealing with the odd naming system was to rename all of those books simply "Realistic Fiction" and call it good. But, now I see that this category is just too big to be manageable. A girl who loves The Princess Diaries has to wade through dozens of books they have no interest in before finding the book they want. I need to figure out a way to divide the Realistic Fiction section into more manageable sections.

It's far easier to identify sub-genres with genres such as fantasy, where you can distinguish between Fairytale Retellings and Epic Fantasy and Historical Fantasy and Paranormal Romance. But, it's more difficult with realistic fiction. 

I'm stumped. So I'll throw it to you. Do you have any ideas for splitting up the Realistic Fiction section into more manageable sub-genres?