Pace and attention
Play at a steady pace and keep your attention on the table. Long pauses frustrate other players, and missing your turn or claiming late slows everyone down. If you need a moment to think, it is fine — but avoid doing it every turn.
Do not draw your tile until the previous discard has been named and had time to be claimed. Drawing early is one of the most common sources of friction at mixed-experience tables.
Clear, honest play
Name each discard clearly, place it where everyone can see it, and keep your hand tidy so you do not accidentally expose tiles. Never touch another player's tiles or the wall out of turn. When you call a tile, call loudly and promptly.
Talking about your hand during play — "I only need one more!" — is considered poor form in most styles. In American play, players may not ask others what they are collecting.
Helping beginners
Experienced players can make or break a newcomer's first night. Explain decisions after the hand, not during; offer to let beginners play with open hands while learning; and be patient with miscounts. Many clubs pair new members with mentors for their first few sessions.
If you are the beginner, it is fine to say so and ask the table to play a little slower.
Winning and losing well
Declare wins clearly and without gloating, and pay promptly. When you lose, avoid post-mortems blaming others for their discards. Over many games, luck evens out, and people remember a pleasant table far longer than a lucky win.
