The Martingale Strategy is arguably the best roulette strategy, and it's certainly one of the most famous ones. Simply put, you don't hold back when you lose; you do the opposite. Whenever you lose in roulette, the Martingale Strategy requires you to make your bet bigger than the previous one.

A roulette system that carries relatively little risk is the red bet  system. You bet a small amount on red and double it every time the ball does not fall on a red colour until you make a profit. In addition, you always bet the minimum amount on black and double it when the ball falls on 0  (or 00 ).