As with any game of pure chance, there is no real effective strategic system for winning at slots. Never believe if somebody says that he has an incredible winning strategy. The game is random and arbitrary. The machines have no memory, so there is no effective way of outsmarting them. But there are some tips, which you can use as a basic strategy. Try to find something above 95%. When playing slots you must always know the odds and probabilities of the slot you are playing. Before you start playing slots get acquainted with the payout schedule. Before playing decide how much you can spend this day. Once that limit is reached, go do something else. You will not be a winner every time you play. Don’t think that machine will feel guilty if you insert a lot of coins and get nothing back. If you think that the machine you are playing will hardly pay anything out you’d better stop playing it. When things are going your way and you're on a lucky streak, take advantage of it and bet more. Don’t make high bets if you are not very lucky with this very slot machine. Play the slot machines that your bankroll can afford. If you have little money you’d better paly dollar machines. Sounds obvious, but a lot of people forget! Never make high bets if you play slots you have never played before.

You must know exactly the game you are playing.
You should know exactly how many coins you are supposed to insert into a machine. Always cash out your credits before leaving a machine.
Only if you have fun your gambling won't be stressful. If you feel lucky increase your bets and vice-versa.