The best way to WIN, is to stay HOME. If indeed, you head out with cash in hand. Set a preset spend amout, plan on how much you can afford to lose.
Some "loose" machines are placed in high traffic areas.
Do not spend time pumping cash into one machine thinking it is bound to hit, it will take your money.
Go with machines with the best odds, and read the machine carefully before you play. Some only pay on with the second pay bet.
HAVE FUN at it, and do not plan to win!