Choose an online betting site on which to place your American Idol bets. Some of popular sites include JustBet, 5Dimes and Bookmaker. On these websites you can deposit money into an account, place your bets and withdraw your winnings.
Decide whether you want to bet on the winner of American Idol or on who will be eliminated in any given week. Betting correctly on the winner has a larger payoff, but betting on weekly eliminations would give you more chances to place bets as the competition progresses.
Determine when to place your bets. The more in advance you place a bet, the bigger the potential payoff. For example, if you choose to bet on weekly eliminations, betting Tuesday morning increases your chances for a big payoff, as opposed to waiting until Wednesday morning after the performance show has aired. Similarly, betting on the winner when there are still 12 or more contestants in the field can potential give a bigger payoff.
Bet wisely by keeping American Idol trends in mind and knowing the voting demographics. You don't necessarily want to bet on who you like best, but who you think people who would pick up the phone to vote like the best.