Defense begins with consistency starting with individual responsibility. Coaches add pressure and multiple defenses to provide different 'looks', alter tempo, and facilitate comebacks.
Each player should understand their assignment and how individual pieces fit the collective narrative. Top priority belongs to NO EASY BASKETS, restated as HARD 2s or ONE BAD SHOT. On any play, the player should be able to explain what she saw*, why and how she reacted.
1. Stance. Coaches teach subtle differences in stance, on and off the ball. But everyone agrees that defensive players belong in a stance. Teaching the 'boxer's stance' makes sense. Play "low to high" and recognize the Kevin Eastman phrase "it's a shoulder's game...low man wins."
2. Position on-ball. Position differs depending when on or off ball. On ball defense begins with ball pressure. No "dead man's defense" (six feet under). If the player has the ball "high", then defending shots and passes is a priority. If the player holds the ball low (below the waist), anticipating driving makes sense.
3. Position off-ball. With rare exception (full post fronting), defenders play basket-you-man with position relative to ball proximity. Some programs preach denial one pass away and others favor sagging (or Clair Bee's floating) with denying drives as first priority. On the "help" (weak) side, defenders orient relative to the ball (level or below) and facilitating protecting blocks and elbows.
Proper positioning means overloading to the ball.
4. *Vision. Both sides of the ball rely on VDE- vision, decision, and execution. Vision precedes action. Players must 'see both', ball and assignment. I don't advocate learning via the means I was trained, although I don't regret it. Coach had a volleyball, which generally found you whenever you lost sight of the ball. That dog won't hunt in 2017.
You cannot stop the ball, help, or recover if you don't see the ball. Losing sight of "both" (ball and man) facilitates back cuts and prevents help.
5. CARE. We teach the CARE acronym. C (concentration) leads to A (anticipation) with R (reaction) a E (execution). I reference a game where an opponent defeated our high school team for the first time, late. The first two defensive series, mental lapses caused failed block outs leading to putbacks for scores. Teams can lose as easily on the first possessions as the last. Win this possession.
Bonus: 2-3 zone offense
Quick ball reversal with top screen creating multiple options.