For me, writing for younger audiences and writing for adults uses two different halves of my brain.
I find coming up with a title the hardest part of writing a novel.
I do a lot of brainstorming with my editors. Sometimes it just comes out in the writing. I'll get an idea as I'm writing the chapter. I try to go for maximum surprises in PLL, stuff you don't see coming. It's a lot of fun!
I'm not sure that I have a favorite either on-screen or in the books! Whenever I'm writing, I'm always really excited to dive back into each character.
It's nice to dig deeper into people who may look one way but always have a story to tell. I obviously write about that a lot.