I didn't overdo it. Six days or so before, I took a FL, and my score was right where I wanted to be. I'm sure I spent a couple of hours looking over information and reviewing, and I probably ran through a couple passages just to stay sharp, but it's not really something you can/should cram for.
I remember the logistical stuff being the real battle. I woke up super early (like 5:50 am) to get used to the fact that I'd have to be awake and lucid for the test, bright and early. I also got a taxi scheduled so that I could get to the testing center on time, for sure, no matter what. Things of that nature.