Disrupt communication through repeated suit plays

Lower level contracts often involve a squeeze endplay; persisting on first lead suit may break communications.

Disrupt communication by attacking entries

Particularly in 3 Notrump game contracts, throwing the dummy in the lead may prohibit establishment of a long suit.

Disrupt count rectification by ducking

At 5 and 6 level contracts when declarer must forfeit the lead to establish a squeeze, the controlling defender should consider ducking the offered trick with other side suit honors.  In addition to possibly breaking the squeeze, the order and timing of the squeeze may require additional declarer guesswork.

Discarding throw in cards

At game through slam contracts when holding squeeze cards, consider pitching a King when partner is known to hold a Queen in order to break a subsequent squeeze

Underleading a winner

When opponent holds threatening secondary honors as Q J x [x] (coup cards), the stronger partner with length in the suit may consider underleading early on, provided partner can ruff a long suit.

Maintain 4 card side suit

Particularly in slam contracts, the honorless partner should keep 4+ card side suits to ensure declarer does not establish a lackluster 4-3 card side suit.

Falsecarding to confuse declarer

Pitching an intermediate honor may lead the declarer to mis-guess honor placement or suit length (Rule of Restricted Choice)