A key to winning at 777 Rummy is knowing when to discard & when to hold onto cards. Players try to make runs and sets that total seven or multiples of seven, so it's critical to evaluate therummy ball potential value of each card in your hand and adjust your strategy accordingly. You can prevent your opponents from gaining an advantage by discarding some cards and holding onto others to increase your chances of making valuable combinations. When deciding which cards to keep & which to discard, it's critical to weigh the possible effects of each card on your entire strategy.