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.
In most slots, the rate is somewhere between 80% and 95%, but some games can exceed 95%. The basics of the return to player percentage indicate that if you bet $100 on a game with an RTP of 94%, you'll win back $94. But again, this is for long-term results since the rate was determined over millions of spins.