For me, it's just been watching as much of the show as possible, playing along, and looking for trends in the question writing. This was especially the case for The 1% Club. The questions become considerably easier when you figure out what kinds of questions they like to ask. For example, if you see a sequence of twelve, it's probably something to do with months. If a sequence of letters seems random, try reading them backwards, etc etc.
Agreed on the writing trends, hence why I tell people to at least try, but not overdo, writing questions/material. Sure, you can't play it yourself, but you pick up on trends, and if it's a quiz show, you end up doing light research on subjects you may have otherwise been unfamiliar with.
For people who I run practice/prep for, I typically throw a wrinkle of some kind in. The game gets unfair, the scores magically change, the buzzers get a little slower- not to cause chaos, but to simulate how to play when things aren't going your way.
On show day, make sure to eat, but try to eat things you're already very familiar with. I've seen someone on a tape date get swapped out mid-game thanks to an upset stomach. Not fun to watch.
