These are some questions that you can use to develop a defensive system and to tweak the system so that it fits your changes in personnel and the changes in your opponents' personnel from year to year
Philosophy
Defensive Adjustments for a team or an Individual?
Scouting or System?
Do we want to have any "junk" in our system?
What are the strengths of our players and how can we best utilize those strengths while hiding their weaknesses?
What is the optimal number of possessions per game for this group?
Can we defend for that number of possessions at that pace?
How is our ability compared to the best teams in our region of the state tournament? our conference? our area?
How do we need to play to advance as far as possible in the state tournament?
What is our depth like?
How does our depth affect our style and pace of play?
What will our substitution pattern be?
Conversion Defense
How many players are we going to send to the offensive glass?
Do we need to add any rules that will improve our conversion?
Do we like the drills we have to teach conversion defense?
Man Defense
What hurt us most last year defensively?
How do we defend dribble penetration better?
What screening actions created problems for us?
Where do we want to pick up the dribbler?
How do we want to defend the post?
How do we want to defend ball screens?
Zone Defense
How much zone do we want to play?
Would it help us to have an even front and odd front zone so we can attack them both offensively during practice?
Do we want to be able to trap out of our zone defenses?
How do we best teach rebounding out of our zone?
1/2 Court Trap
How much do we want to play it?
How big are our trappers?
How do we want to rotate out of the trap?
Do we want to stay in the trap or go "one and done"?
When do we want to look to play it - dead balls, FT's, end of half...
Do we have a better trapping line-up than others?
Presses
How much do we want to use the press?
When do we want to press?
How aggressive do we want to be with our press?
Do we have a better pressing line-up than others? Who are our best trappers?
Do we deny the point guard back once they pass out of the trap?
Inbound Defense
Do we want to play strictly man?
Do we want to trap the inbound pass?
How do we want our inbound defender to play UOOB and
SOOB?
Special Situations
Who would be our best denial defender?
Does any team on our schedule potentially warrant a special
defensive tactic?