PAX Prime 2010 was my first PAX, but I didn't go in blind - a number of my friends are well-seasoned PAXers, so I theoretically knew what to expect. Theoretically. Because even though I had heard tons of stories and gotten tons of advice, it was still very much OMGWTFBBQ!!!
Best advice I was given: you can't see and do everything so decide on a couple things you don't want to miss and focus on those; celebrate and be excited for what you saw, don't regret what you missed.
The first day I lined up to get into expo hall, just so I could be part of it all. And lo and behold I was standing next to AngieK, who I only knew from Twitter and this blog. Throughout the weekend I met a number of awesome people that I knew from Twitter.
I spent a fair amount of time in expo hall, getting lost over and over. The cool part of getting lost is I kept stumbling across booths I had missed. I played a number of game demos, mostly from smaller publishers. The big titles (like Portal 2, Duke Nukem Forever, etc) had huge lines for the demos so I didn't want to wait for an hour or more to demo a game I will likely buy when it comes out. The other great part of talking with the smaller booths is that you were often chatting with the game developer themselves, and when they talked you could hear the excitement in their voices.
I only went to two panels: the Of Dice and Men play and the Acquisitions Inc Live D&D session. I had previously heard a number of people complaining about the lines at PAX. I lined up for over an hour and a half for Acquisitions Inc, but honestly the lineups are half the fun of PAX. You don't need to be an extrovert, just start a conversation with the people next to you - remember we are all geeks/nerds. I played a number of rounds of Zombie Dice, and then a card game called Pancake that one of the guys we were chatting with had just developed.
The rest of the time I spent in tabletop and the secret RPG level. I played a D&D Delve with some twitter friends, and then tried the new Gamma World - which was a total blast. I played a Seismic Felinoid (basically a rock kitty) and we defeated the bad guys. I learned to play Poo! The Card Game, Forbidden Island and Dominion; I liked Forbidden Island so much I bought it when I got home. We played an awesome new miniatures based rpg called Super Dungeon Explore that was a ton of fun.
I feel like I might be repeating myself here, but there was NOTHING that sucked at PAX - I enjoyed everything I saw/played/lined up for.
To summarize: PAX is amazing, have no regrets about stuff you missed, and talk to people. I can't wait for Pax Prime 2011!!!