While it's possible to use math and statistics to improve your odds at Roulette, it's important to keep in mind that the game is designed to favor the casino. The house edge in Roulette is typically around 2.7% for European Roulette and 5.26% for American Roulette.
Outside bets in roulette carry the lowest risk. They cover more numbers yet the payouts are lower (1/1 for Red, Black, Odd, Even, 1 18, 19 36). These outside bets carry the best prospects for long-term wins.