Hello from someone who attended the Las Vegas Fan Fest. Here's some useful advice:

(1) Bring your 3DS or Vita. You're going to be waiting in line a lot. A LOT.

(2) Buy your soundtracks early. They sold out on the first day of our event. The moogle plushie sold out halfway through the second day.

(3) Bring your own water bottle. They have these water coolers against the wall that you can refill all day and you will get thirsty.

(4) The line for Odin will be very long. If you are VIP or know someone who is VIP, get in line right away after you buy your merch on the first day. Also bring a premade of your friends who know what they are doing. It helps a ton, you are given very limited time to attempt the fight and they separate the line into first-time attempts and repeat attempts and obviously first-timers get priority.

(5) Don't skip the costume contest. We had amazing ones at the Las Vegas event, you guys will probably have the same.

(6) Don't skip the closing ceremony. Trust me.