How to play Rummy well once you know the rules: the decisions that matter, and the habits that win.
When somebody goes out, every card you hold counts against you, and court cards count 10 each. A lone king or queen that is not part of a pair or a run is the first thing to throw. Low cards are cheap to keep: an ace costs one point if you are caught with it.
The early turns are the time to do it. Nobody is close to going out yet, so a high discard is unlikely to help anyone finish, and your hand gets cheaper with every turn.
Taking the top of the discard pile shows everybody what you want, and the same is true of the other players. A player who picks up a seven is building sevens or a run around it, so hold on to the cards next to it.
Keep an eye on how many cards everyone holds. A player down to two or three cards may go out on their next turn, and that is the moment to lay off and throw your highest cards, because anything still in your hand is about to be counted.
Laying melds down protects you: cards on the table cannot be counted against you. It also shows what you are collecting, and anybody may lay off onto your melds to get rid of their own cards.
Holding everything back to go rummy doubles your score, but only if you get there before somebody else goes out. If you are close — one card away with a cheap hand — the gamble is often worth it. With a lot of points in your hand and other players shedding cards fast, put your melds down.
Every meld on the table is a place to get rid of cards, whoever laid it. The fourth card of a set or the next card of a run is a card that no longer counts against you, and you do not need a meld of your own first to do it.
Look at the table before you decide what to keep. A nine of hearts is dead weight in your hand but safe to hold if there is a run of hearts ending at eight in front of somebody else.
When the table plays aces low only, an ace fits in just one run, ace-two-three, and a queen-king pair needs a jack. With aces allowed at either end, an ace is a flexible card that still costs only one point, and it is well worth keeping.
On this site the stock is turned over once. After that the table says these are the last of the cards, and if they run out nobody scores the hand. A player who is well behind on a hand may be happy to see that happen, and a player close to going out should hurry.