The last bit of writing to squeeze out of the Eclipse Phase one shot. The title isn't an exaggeration, I suck at running convention games, I can never balance the time slot requirements to the amount of stuff to do with the plot seeming not too unreasonable and not crazy.
The two key items I'd say for running a convention game are to: 1) Know the rules; 2) Know the module/adventure you are running - everything else can be generalized to running any game. Note by convention game I mean a one or two shot game run in a specific time slot (usually 4 hours) with a group of people who probably don't know each other.
Key Item #1: Know the Rules
Now if I'm the DM in a long running campaign, I don't neeeeeed to know the rules. I should know the rules; but given a general set of players, I may be able to outsource detailed rules knowledge to one or more of the players, and/or trust them to each handle their own character specific rules themselves. You may not be able to, stories abound of DMs who have players that can't be bothered to learn the rules, but even through osmosis you'll pick something up.
With a convention game, you can't guarantee everyone is going to know the rules, or even if they know the basics, whether they will know the exceptions to the rules. This means you must be on top of the rules, and if you are modifying them to be easier to run in the module, you need to announce that up front.
The Eclipse Phase GM failed to do that - he didn't know and didn't like the combat rules for an adventure that was advertised as combat heavy. These things do not work well together.
Key Item #2: Know the Module/Adventure
Know what you are running. This is probably one of those that could be more universalized to any game, but there's more slack in a campaign, a single bad session is unlikely to deep six the game assuming a good group of gamers. But yeah, I had a poor time of it at the game because the module was poorly designed (it was apparently an unadvertised beta test) and the guy running it hadn't gotten it with enough lead time to know it properly. Now you can, sometimes, get away with either knowing the module, or having a well written module but not both, but having neither dooms you to failure.
As a side note - if you are going to be using pre-generated characters make sure they fit the theme of the game, nothing is worse than being the team of bio-engineered sex slaves in the middle of the fifteenth fire fight of the night or the grumpy mercenary cabal forced to deal with subtle politicians. Well it can be fun, but it requires lots of thought and planning to integrate properly.
Bonus Item #3: Sell your Adventure Correctly
I wrote an entire post on the taxonomy of adventures previously, so I won't go too heavily into this; however, ultimately, labeling the game provides certain expectations of themes and tropes that are going to be used. Now you can either play to the themes, which is highly suggested, by me, for a short 4 hour game, or you can try to be cute and play against type. But once again, if you are going to do the latter in a 4 hour game, you need to be very, very sure of what you are doing.