1. In transition adjustment, try to beat the offensive post-up player to the player's favorite spot to set up post position.
2. The use of foot movements is very important. A defensive post-up player should be ACTIVE and adjust his position as the ball moves.
3. A post-up defensive player should communicate the exact position of his opponent.
4. A defensive post player should contest the path of his opponent. Never allow the post-up player to move directly to a position on the strong side without some type of impediment.
5. A quick-moving defensive post player can confuse the offensive post-up player and the passer by varying the position of post play.
6. A good defensive post player should never lose sight of the ball.
7. The most important rule of all for a post defensive player is proper stance, vision and mental requirements. Stay low in a flexed-knee position, arms extended parallel to the floor, midpoint vision on the weak side, and anticipating movement of the opponent.
From "Basketball Post Play" by Pete Newell and Tom Newell