5 mistakes new mahjong players make
The most common beginner mistakes in American mahjong are picking before the last discard is settled, calling a tile you can't use, passing a joker in the Charleston, misreading the card, and declaring mahjong without laying the hand out for everyone to check.
1. Picking too fast
Wait until the discard has been named and nobody has called it before you reach for the wall.
2. Calling a tile you can't use
Before exposing anything, make sure your whole hand can still be finished. An exposure that fits no hand makes your hand dead.
3. Passing a joker
Jokers can never be passed in any part of the Charleston.
4. Misreading the card
Read the notes in parentheses and the colours before committing to a hand.
5. Declaring mahjong wrong
Say mahjong, lay the whole hand face up, and let everyone check it before anyone pays.