Modifying Your Gaming Style. Understanding when to play aggressively and when to play defensively is a crucial part of becoming a rummy expert. While playing defensively entfishing slotsails holding onto your cards and attempting to prevent your opponents from going out, playing aggressively entails trying to go out as quickly as possible by forming sets and runs. Being able to discern when to employ these two tactics can offer you a notable edge in the game. It takes a combination of skill, strategy, and luck to win at rummy.