Your chances of getting on the show increase if you're not the typical nerd:
[T]hey want people with a combination of traits: a deep knowledge well, the ability to retrieve an answer quickly, unflappability, a decent personal presentation and personability. … If contestants were cast simply by rote memorization and rapid-retrieval abilities, you know the result, because you see it at technology trade shows and engineering colleges: a row of people, mostly men, would affectlessly and rapidly answer every question as fast as possible and seem somewhat unsympathetic. They might not even scream or smile when they won. That's not good TV. The show wants people who have a few interesting stories about themselves, and to whom the 10 million or so home viewers will be able to relate.
After you've been selected, here are some tips for precision cramming:
[A]reas that feature most frequently … include popes, potent potables, royalty, recently popular songs, state mottos and capitals, major rivers and presidents. Determined not to be tripped up Babbage memorised facts about the nutmeg state (Connecticut), the components of a White Russian (vodka, cream and coffee liqueur), German rulers (Otto von Bismarck and Kaiser Wilhelm often come up) and wars, especially those just around 1900 for which the show's writers seem to display a particular fondness. He also used the J-Archive to simulate hundreds of games.
In addition, Babbage took Mr Harris's strategic advice to scan category titles to fill one's head with possible answers, and to deconstruct clues the instant they are revealed to pick out the key words and phrases from those inserted as a distraction. Crucially, Mr Harris writes, never ring when you do not know the answer. A wrong response leads one to lose the clue's value and potentially give away the correct response and the cash to another player.