By Eddie Kantar 
Courtesy of KantarBridge.com
1. Never, but never, forget you are playing with a partner. It pays to consider what things may look like from partner’s point of view, particularly when you are privy to information that partner isn’t.
2. You cannot defend proprely unless you remember the bidding.
3. You cannot defend properly unless you know what system the opponents are playing.
4. You cannot defend properly unless you watch the cards, particularly the little fellows.
5. You cannot defend properly unless you count.
6. You cannot expect your partner to defend properly if you make faces or show other signs of disapproval.
7. Keep one goal in mind: DEFEATING THE CONTRACT. Do not worry about overtricks unless you are defending a doubled contract or are playing matchpoints.
8. A player who hesitates during the bidding is likely to have a problem hand. Keep the hesitation in mind.
9. The figure to focus on during the defense is the number of tricks you need at any given moment to defeat the contract. Defense is based on this figure.
10. Give your opening lead a little consideration. The fate of many a contract is determined by that one card. Use the bidding as a guide.
11. Make sure you and your partner are on the same wavelength concerning leads and signaling conventions.
12. Don’t compound a crime. If you, or more likely partner, has made an error, do not lose your cool. Many contracts can still be beaten after one defensive error, seldom after TWO.
13. If partner makes a nice play, a kind word or two at the end of the hand goes a long way.
14. The speed of the play, may be a clue to declarer’s problem. When playing a 4-3 trump fit, play usually slows to a crawl.
15. When two possible defenses present themselves to defeat a contract, both equally likely, select the simpler. (Unless you are looking to make an appearance in a newspaper column.)