To use the "high-low" card counting system effectively, you assign values to the cards dealt: +1 for cards 2-6, 0 for 7-9, and -1 for 10s, face cards, and Aces. As the cards are dealt, you keep a running count by adding or subtracting based on these values. To make the count more accurate, you calculate the "true count" by dividing the running count by the number of decks remaining in the shoe. A higher true count suggests a deck rich in high cards, which benefits the player, so you increase your bets. Conversely, a negative count favors the dealer, and you should bet smaller amounts. Additionally, you can adjust your playing strategy, such as standing or doubling down when the count is high, or hitting more often when it's low. Consistent practice and staying discreet are key to mastering card counting and using it to your advantage.