Oh, my naive friend, if everything were that simple, the casinos would have gone bankrupt long ago. You are playing against an algorithm that is designed to ultimately win. So if you don't have a strategy other than 'lucky/unlucky', then you've already lost.
Yeah, and how many of them then left the same thing in the same casinos? Remember, every gambling success story is just the tip of the iceberg; underneath the water lies a darkness of losses and broken hopes.