Recognizing patterns in your opponents' gameplay is just as important as keeping track of the cards. You can learn a lot about their tactics and goals by wrummy toatching which cards they pick up or discard. An opponent may be trying to form lower-value melds if, for example, they routinely discard high-value cards. You can make more strategic choices about which cards to keep or discard by fusing your ability to count cards with astute observation of your opponents.