Inspiration? I'll start with music.
Not only does it inspire me, it drives me. It's like a trigger that helps me jump back into the world of a novel-in-progress. When I'm facing writerly difficulties, that trigger is invaluable. I often have music on in the background while writing--but only particular music, very quietly, stuff that I know so well that it becomes soothing white noise after a while, but helps create a general mood.
So. For The Blood Confession, I needed to inhabit the mind of a murderous young woman who kills her servants and bathes in their blood. Erzebet sees these servants as disposable, has little remorse for her actions, and is obsessed with her own beauty and her fear of death.
Bjork's "Human Behaviour" seems to capture Erzebet's distance from the humans around her, seeing herself as something separate and all-powerful. Also, Bjork's voice is gorgeous and crazy. (The video is as bizarre as you might expect.)
Tori Amos (more gorgeous and crazy) was also a stand-by during this process. And Mozart's Requiem Mass took center stage--so dark! So gothic! So thrilling! The music of angels...and maybe of devils, too.
Finally, every book has a theme song. Not a song I listen to while writing, but pre-writing, to boost moral. This book is about the evil queen in the fairy tale, about seeing the story from her bitter and deranged point of view and finding some way to empathize with her. Erzebet's theme song was obvious. I know that she lived in the 16th century, but I think the bloody Countess would have loved this one.