Writers have rituals. Some of it has to do with the actual writing like always doing so many pages a day or always playing music. Some of it is just superstition. :-)
Like the baseball player that's on a hitting streak and won't change his socks until he has an 0-for night, writers have quirky little behaviors. Or maybe I should qualify that as some writers because I certainly can't speak for everyone.
What are my quirks/rituals? I always have to have a picture of the hero and heroine when I'm working. Usually before chapter four, although I had one book where I didn't find an image of the heroine until nearly the end and I was obsessed until I did find exactly the right shot. That's one of those things, though, that can teeter into a real process if you're drawing a line. I use the pictures to keep details straight about the h/h, and since I'm not particularly visual, they help me describe things.
Other quirks? I always have to post dancing Hobbes on my blog when I finish a book. I always have to move the pictures of my hero and heroine from the Characters In Progress page of my personal web space to the Characters Living HEA page. I nearly forgot to do that with Shona and Logan, but did it tonight. If I didn't, bad things might happen.
I have to send my finished chapters to my writing buddy the minute they're done even if she's out of town because I can't seem to move forward until she has them. Once the chapter is sent--no problem.
I think those are the extent of my little rituals, but I might be missing some. It's easy to overlook them in ourselves, I guess, because anything we do is normal, right? ;-)