If you can, run it with friends before you take it out on the road. Observe the pacing, see what ideas they come up with, get some feedback on how they feel about it.
Have a couple of extra pre-gens to spare, both for variety and as backups if someone manages to be particularly creative at getting their character into trouble in the first encounter.
Have some visual aids to hand, maybe images and names of major NPCs as you introduce them, and maps or landscape images for scene-setting. You don't need to go full battlemap, but you're going to be running for a bunch of people who don't know each other, some of whom may be pretty wiped out (either from travelling if it's the first day, or late nights if it isn't), in a noisy convention hall where they may not catch your every word. Anything they can grab onto in order to visualise the game is going to help keep their head in your setting.
Be prepared to respond if someone suddenly comes up with an out-of-left-field idea that circumvents a situation - or if they completely fail to puzzle their way out of what you thought was a straightforward set-up. If either you or they are becoming flummoxed by an unexpected turn of events and things are in danger of stalling, that's a good time to suggest a pee break, and come back to the table with a fresh perspective.
Ultimately, at a convention you can't pick your players. You hope that they all signed up because your game sounded really cool to them, but sometimes you'll get the ones who just put their name down because your game had a slot free and they didn't want to sit around doing nothing for four hours. Do your best to entertain them and deliver the experience they're looking for, but know that they're also responsible for their own fun, and you won't always click with everyone. If the majority of your players walked away smiling, or still talking about the game, take the win.