Coaches from elementary school to the NBA use variations of SHELL DRILL to teach defense. But shell drill teaches defense, offense, and communication with a little imagination. Variety helps players see the game through different lenses.
Practice key elements. Princeton coach Pete Carril held that man-to-man defense 1) contains the ball, 2) controls screens, and 3) challenges shots.
The BASE shell drill tests:
1) defensive stances, ball pressure, and core position (ball-you-man, ball-you-basket)
2) drop to the level of the ball
3) load to the ball (helpside "I")
The simplest iteration passes the ball around and skips to reposition defense. Generally, we play "LIVE" shell, with all scoring options allowed. Everything starts with ball pressure and containment. A team that can't contain the ball will never defend well.
Add difficulty with passing, cutting, and filling.
More difficulty ensues with off-ball screens. Coaches decide whether to teach lock and trail, going through or under the screen, or selective switching. I teach weak side defenders to go under or through.
"Whistle off" a defender to create a 4-on-3 scenario requiring recovery. You can disallow the defender from returning into play.
Add a designated screener to create more complexity.
Shell 3-on-3 with doubling...help...and recover on the pass. 3 consecutive stops to win. Run at multiple baskets...to involve everyone.
Find other variations that work for you.
Lagniappe: Regular execution of routine plays defeats the occasionally spectacular play.
"Focus is more important than genius and there are perennial winners at every level of basketball (and other sports) from high school, to college and to professional who exemplify this. Their “genius” is their ability to focus when other coaches and programs around them give in to distraction."
"It's the economy, stupid."
"Rule 1, don't lose money. Rule 2, never forget rule 1."
"The Low-cost airline."
"Keeps going and going..."
"Democracy dies in darkness."
Football: "block and tackle."
Pitching: "work fast, throw strikes, change speeds."
Basketball: "get quality shots and deny easy shots."