The key to winning at Roulette is to avoid playing long enough for the house edge to work against you.
The longer you play, the longer the house edge has a chance to siphon off your money, so it is important to seize upon lucky moments and get out while the getting is good. The fact is that Roulette is a negative expectation game. This means that there is no way to shift the edge from the house to you, like you can if you play perfect blackjack.
You can, however, reduce the odds against you by playing boldly.
As the house edge will break you over time if you take your gambling money and space it out over many small bets you are stretching out the time you are playing, putting the odds in favor of the house edge getting you.
If you instead place fewer, larger bets, you increase your chances. The fact is you will have to get lucky. The best odds of winning is a double-bet choice, like betting on red/black or even/odd. You have slightly less than 50% chance to double your money.