The most exciting aspect of writing YA is that there are no boundaries to limit. My writing career began in literary fiction, and I was constantly hearing form editors that certain topics, conventions, or narrative styles were “anathema.” I quickly tired hearing about what I couldn’t do as a writer. When I began writing novels, I chose YA because the field is open to topics, styles, and narrative structure. What to write first person present? Go ahead. Want to write a historical using the epistleary style? Go ahead. Want to write in a mix of narrative and graphic storytelling. Be my guest.
I don’t consider YA to be a genre, but a marketing category. Because of that, there are no universal tropes. You will find genres within YA, and those have tropes. Sometimes, I try to escape a troupe, as I did in Soul Enchilada by making a demon neurotic and nerdy, and sometimes, I embrace the trop and try to have some fun with it, as I did in Black Hole Sun when I named a character after an internet meme.
No matter what, fi you write YA, a writer should never pander to readers. Teens have finely-tuned BS detectors, and they distrust writers that aren’t honest with them. The best thing to do is write the book you want to write and let the boundaries worry about themselves.