Find a roulette table with a high max bet and a small minimum. Bet a small amount on black or red; even or odd; or 1-18 or 19-36. Keep your wager on the same spot on the table until you hit it. If you keep losing, keep betting a very small amount.
One strategy many Roulette players use is they will make one bet on 19-36 and then on various numbers that are 19-36, so if a number hits they will not only get paid out 1 to 1 on the 19-36 bet, but also on the number they hit on. Before you play Roulette you need to find out what the minimum and maximum bet is.