On the one hand you have to be aware that your own money is always at stake. You should set the limits so that you really get something out of your bankroll. For example, don't play with 1 Euro spins if you only deposit 20 Euro. Then you should only play on slot machines with the highest possible RTP (payout ratio). You also need to think about the right payment method. You can use credit cards as well as eWallets à la Paypal, Skrill or prepaid cards like Paysafecard.