By now, you know what mood you want to set. You know your words. You know the color that evokes that mood. Your politics contribute to it. Your plot even assists it. And if they dont, today is the day to make sure they do.
Go through your notes and make a "m?" note next to anything that doesn't actively fit into the mood you want to convey. It's all right to have mismatched moods, of course; in many ways, it's crucial to have a variety. But you want to know, when you write your novel, if a particular element is going to dilute the mood or not.
Find a drawing or piece of artwork that captures the mood of your piece and print it out, preferably in color. Hang it on the outside of your notebook or near your desk. This might also be a good day to put together your moody playlist.
Also, check out the Bonus Exercise about burnout and what to do when you're going crazy over the details....