Only play the slots that have the highest RTPs (such as Mega Joker) and only play with a valuable deposit bonus in your account. This is the only practical way that slot machines can be beaten to guarantee you a profit in the long run. It’s not easy to achieve though. An alternative way is playing progressive jackpot slots when the jackpot has reached a high enough amount. The jackpot has to be really high though for the game to have a positive expected return and even if it does you are required to actually hit the jackpot to profit. This is easier said than done.