To know when the deck is in your favor while card counting, you need to track the running count, which helps you determine if more high cards (10s, face cards, and Aces) or low cards (2s through 6s) are left in the deck. A positive running count indicates a higher proportion of high cards, which benefits the player by increasing the chances of getting a Blackjack or winning hands, while a negative count suggests more low cards, which favors the dealer. Many card counters also calculate the "true count," which adjusts the running count for the number of decks remaining. A higher true count signals a deck that is more favorable to the player, allowing you to increase your bets accordingly.