Blackjack is one of the casinos' most popular games. Many people are intimidated by the rules of the game and do not fully understand the methods behind trying to beat the odds with this card game. So, they shy away from playing in public or make error-prone gambles.
Many people simply match the dealers' bets --for instance, hitting on 16s, staying on 17s, and never splitting or doubling. This, in reality, will actually cause you to lose about 10 times more than if you follow a "players" strategy rather than a "dealers" strategy.
This is because you have to keep in mind that the odds are still in the house's favor.
Several methodologies and charts have been devised. One of the most common (and proven) is shown below. Don't worry... you can carry this chart with you in to most land-based casinos too (so, you don't have to memorize!).