I know there is a lot of this stuff already on here but I just wanted to reiterate a few myself.
First, thanks a ton to everyone on this forum. I took the AT-SAT yesterday and have been reading this forum for a long time.
Now, as far as the test goes, here are a few things that I will reiterate:
1. The proctors (Robinson Aviation) people DON'T care what you wear. Make yourself comfortable! They did an incredible job making all of us feel comfortable and went out of their way to help us get lunch and what not.
2. If your driving from a distance, get a hotel room at the hotel they are testing. This is the smartest thing I did (being I had six hour drive). It eliminates a lot of stress.
3. I know this is hard, but don't stress yourself out. Your not competing with everyone else in the room, your only competing against yourself. Stressing causes no good....
Also, to each his own with the green book. My advice, don't kill yourself practicing and studying. I don't think it would be valuable as the test runs slightly different than the software. However, I found it VERY valuable to at least know whats coming.
As far as the test itself, the dials, math, angles, and scan all were faster than I thought they would be (meaning they were relatively short). The letter factory goes on FOREVER and asks different questions (nearly impossible) than the software. The ATST I was fearing, but ended up being my favorite part of the test. The analogies were as difficult as everyone makes them out to be, but you'll get through.
I took the test yesterday so if you have any other questions, ask them while its fresh.