Reverse Martingale or Anti Martingale
Try to limit yourself to short streaks of 3 or 4- if you know when to stop, the system can work if you are having a purple patch. Mix it up a little. Stop after 2, then reset. Then stop after 3, etc. Try and randomise it.
Financial traders often use a variant of this system if they see the market trend heading one way. They might start off by hedging their bets and going long and short (betting the market will go up and down). And if the market takes off one way, they´ll increase the value of their position in that direction.
Rememeber, though, that the game of roulette is a game of chance and each spin of the wheel is a mutually exclusive event. You should only be making loose compaisons to trading on the stock market!