Don't drink too heavily or stay up too late. If you've gone there to bowl, leave the entertainment for another time.
It helps to get your mind right before you bowl, that you may have to grind-out every game. This will help you from being taken out by your own frustration. Too many have a single bad game and then can't conceive they can make up for it later. Spares may become more important than strikes.
Relax! Sport patterns don't require speed. They require accuracy. aim small, miss small. You're not going to open-up a sport pattern. So, keep your ball in play by hitting the pocket the best you can. Avoid hitting the nose or throwing wide and leaving washouts. The pattern may get easier later, but don't depend on it.
Avoid poor pin count. 'Bucket' combinations and 3-6-10's or 3-6-9-10's really add up if you leave them too often.
Don't use equipment that's too jumpy. If you're targeting close, you don't want equipment that will take off when it comes off the pattern. Better to hang a weak 10 than a 4-9 or 4-6 combination.
If you don't know how to play inside, learn before you go. Where I bowl, we can arrange to have a pair of lanes set up with the 'Open' shot so a person can get a feel for what to expect. If you can arrange something like that, do so. If not, ask anyway.
Pace yourself. Don't get caught up in the misery around you. If those you're bowling with are bowling poorly, getting off the lanes will be more important than extending the misery. Don't get caught up in their efforts to get off the lanes and go drinking and gambling.
There aren't any single 'big' items that will guarantee success. Instead, there are many little things that if you take care of will keep you from taking yourself out of the game.
Don't get there and be surprised by how tough the shot is. Instead, prepare beforehand for that tough condition. Have a plan and do your best to execute it.
If you start stringing strikes and people begin to gather behind you and a guy is setting up a camera
, keep your head :-)