Despite the fact that so many gambler seem to swear by a foolproof roulette system, the truth is, none exist.  Each spin of the wheel is an independent event, and all bets associated with that event have an in-built mathematical house edge.  If systems that guaranteed success did exist, do you think every casino would offer Roulette?

This is not to say that you don't have a good chance of winning at roulette, because you do. It is actually a great returning game for the player.  

Good luck!