I'm going to have to agree that the best way to win is not to play.
There are systems for advantage play in video poker, but even at a maximum advantage, the player is still competing with an insurmountable house edge (even if that edge is only 1.5%).
Slots are a total waste of time. I'm sure it's great the the bells go off and the jackpot pours out, but it's much more likely that you will simply build those progressive payouts and go home down.
If you're looking for serious casino advantage play, try blackjack. Start with "Beat the Dealer," and find a system that you're comfortable with. Just be careful, or you'll find yourself escorted from the casino.
Your best bet for making money in a casino is, believe it or not, the poker room. With the explosion of poker's popularity these days the fruit is ripe for people dedicated enough to learn how to play the game properly and exploit their opponents.
Good Luck.