Seven come eleven is a popular saying that can be heard at the dice table to attract luck. The meaning of this expression is simple the first roll in each session is victorious when a player hits seven or eleven. Other popular sayings that are common among gamblers: Bet the farm.
The best way to increase your odds of winning on a slot machine is to not play. The probability of winning on any spin of the game is set by the game's program, and nothing you can do will affect that. The game is always set so that in the long run the machine will pay out less than what is wagered.