Having said that I am a slot player and will leave my "technique" here which is choose a game provider that gives more often than other providers the bonus round and also has an hit frequency of 35% or up,this way you will play longer and have more chances to win.In certain casinos this can also be useful for upgrading to the next level and unlock rewards faster.
The "hit" percentage is something that I started to get more interested in and look for it in slots, but it is something that not all providers or casinos them show in information on the screen or at least not all slots provide it.
My strategy for Slots is pretty simple; bet of $0.01-$0.05, and, many spins or few if a big multiplier manifests, then if that win allows me I look for my favorite slots for bets of $0.1-$0.2 (some exceptions of $0.5-$1) until that gain brings me to my positive RoI wishes or at least breakeven. And when there is excess luck (read: five-figure multipliers) that exceeds my betting limits, I withdraw money.
I think there is not a lot of rocket science with the Slots, the other(s) strategy(s) is have fun!, don't spend money you can't afford to lose!, which is one of the main things that will happen most of the time, you should understand it, so there is no 100% winning strategy. Well! at least of course you bet once, win and never again in your life make a bet.