Have you thought about your centerpiece yet? If you choose a centerpiece that requires fresh flowers, make arrangements with a local florist to pick them up the Wednesday before Thanksgiving. You don't want to count on them having any left on the spur of the moment.
In my case, I don't plan on spend much time the night before Thanksgiving working on a centerpiece. So I'm choosing something I can assemble several days in advance.
I've decided on something similar to the last picture in this post of Thanksgiving centerpiece ideas.
So, I've added apples, pears, cranberries, small decorative pumpkins and gourds, pomegranates, mixed nuts in shell, and pillar candles in a soft orangish-brown to my grocery list.
Here's the picture again as a reminder. The nice thing about this arrangement is that it's all reusable the week after Thanksgiving.