Casino slot machines typically have the highest payouts at 95%. This means that for every dollar you put in, the machine is programmed to give back 95% of it at some point. Other gambling locations such as airports, bars, grocery stores, and service stations typically stock machines that have a 50% to 75% payout.
The truth is that there is no trick to slot machines. They provide random results based on set mechanics and it all comes down to luck. With that being said, not all games are the same, so picking the right options is key, and you can still change the size of the bet throughout the session for better results.