Because the truth is, I become obsessed with my projects and I need to absorb them through all of my senses. Since I am very visual, I often create a collage of images that helps put me in the world of the story. Here is the collage for the one I'm working on now:
Yes, it's fairly ironic that there are so many old men in there when it is a YA, but what can I say? Most of the men of political power in Medieval France were old. Or at the very least well-seasoned. Some of the images are thematic, the masks for example, and obviously many of the images evoke the decadence of a royal court rather than feature the correct historical costume, but it works to get me in the story when I need a jump start, a touchstone, if you will.