I travel to many different conventions and find myself organizing or GMing at them. Here's some advice I can give to GMs who are traveling to a con. If this is repeated elsewhere, I'm sorry.
1) Read the mod. Read it before you get there and again at the con before you run the game. Reading the mod before you get there allows you to do the following.
2) Prepare the encounters. I note the encounters, monsters, and traps. I set aside monster figs that I know I'm going to use for a particular encounter and keep them ready. One way to organize is to use ziplock bags with post-it notes or note cards noting the encounter.
3) Prepare the maps. I either draw them out ahead of time and move a book to 'reveal' the map to pcs or (recently) shell out $0.75 for a black and white rendition of the map at the local Fed-ex. Drawing the map saves on precious time.
4) Prepare the certs. Sign everything on the bottom.
5) Know your GM number, know the event code, and write your name legibly on the paper in case a player has questions.
6) Have fun. What's the point running a game if you aren't going to have fun? Don't turn off the next greatest GM because you are having a bad day.