Counting to Thirteen

Every hand has thirteen cards in each suit. That sounds obvious, but most defensive mistakes come from not counting them. When dummy comes down, count the high-card points you can see, add what declarer has shown in the auction, and work out what partner can hold. Once you know partner has at most a jack, you stop hoping for miracles and start planning a real defence.

Practise this on every board, even the boring ones. After a month it becomes automatic, and you will find yourself knowing declarer's hand before trick five.