Here are some other miscellaneous tips to help you cut down the house edge while playing on slot machines.
Start off finding a slot machines that pays double for two coins played. Decide what your total bankroll will be before you start playing. Now start playing the slot machines. Play with one coin at a time until you win. When you win, play with two coins, one from your original bankroll, and one from the previous winnings. Continue playing with two coins until you lose, then revert back to using the single bankroll coin.
After you have played your entire bankroll, count your winnings. If you won more than your starting bankroll, put aside your winnings. Good work. However, if you wound up with less than your starting bankroll, this will be your new bankroll. Find another slot machines and try again.
If you do end up with no coins, quit for the day. This system does not guarantee you will be a winner. It will however help you stretch your playing time while risking less of your bankroll on one slot machines. If you only want to play slot machines for a little fun this might be the system for you.