Following perfect basic strategy can reduce the casino’s edge to about 0.5 percent Play the table with the least number of decks. How to Win in Blackjack: You need to learn (memorize) and always use the Blackjack basic strategy. Las Vegas casinos offer three varieties of Blackjack: Single Deck 21, Double Deck 21, and Multiple Deck 21. The object of the game is to have the two cards in your hand add up to more than the two cards in the dealer’s hand – without exceeding 21. In Blackjack, everyone plays against the dealer.