The most realistic ways to gain an edge over the house are in blackjack and video poker. In either game, you must follow proper strategy and have a healthy respect for the odds. If it were easy everyone would be doing it. I'm not going to say that every player should avoid games with high edges like keno or nickel slots. However, I will state emphatically that sucker bets like the longshots in craps and the side bets in Caribbean stud poker and let it ride should be avoided.
Gamblers talk with fervor about different kinds of systems.
There is always a new system that seemingly works better than the old one. In the long run the ratio of money lost to money bet will always approach the same constant on the same game. All systems either trade a lot of small wins for a few huge losses, or vise versa. A player may prefer one system to another, but in the end the results will average out no matter what system he plays. Binion's Horseshoe in downtown Las Vegas, despite the fact that they no longer allow me to play blackjack there.