Forgetting the pair or yaku
Four sets with no pair do not win. In riichi, a complete hand with no yaku does not win. In American play, a hand not on the card does not win. Check before you commit.
Keeping too many options
Holding on to every tile "just in case" leads to hands that never become ready. Throw isolated tiles early and commit to a direction.
Over-calling
Calling every possible pung or chow produces exposed hands with little value — or none. Call with purpose.
Ignoring the table
Watch discards and exposures. If an opponent is clearly building a flush or has declared riichi, adjust your discards.
Miscounting
Count your tiles after each call and kong. A wrong count can make your hand dead.
