The best slots strategies consist of increasing the size of the bet after losing. You can do this in small increments after a loss, or increase the betting level after five consecutive losses. The goal is to win more from a larger bet and thus cover the previous wagers.
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.