In general, it's best to pick the machines with the highest payouts. Search online to find specific machines that are known to have a high RTP ( return to player ). Pay attention to volatility, too. Low volatility slots have a higher chance of winning, but high volatility machines usually offer a bigger payout.
"If you hit a substantial jackpot, the casino will ask for two forms of identification, usually a driver's license and Social Security card. This is in keeping with certain IRS regulations regarding jackpots ofR$1,200 or more.