The real trick to roulette is to get lucky, then quit while you're ahead. Every spin has a 1 in 37 (for European) or 1 in 38 (for American) chance of landing in a given pocket.

Dealers must have a working knowledge of both the casino rules and the procedures of casino games. They should be trained in various table games including blackjack, poker, roulette, and baccarat. This training can be obtained at accredited gaming academies, dealer schools, or through in-house training programs.

Skilled roulette dealers can influence the outcomes by section shooting  or steering the ball.  It requires a great deal of experience and practice, and it's prized by some casinos to help manage a player's winning streak, but not sought by others due to the possibility of collusion with players.