"Ideas are the currency of the future." Successful people are constant learners and study both success and failure to garner more of the former and less of the latter. In the Navy, we were sometimes required to do "JAGMAN" investigations. In a JAGMAN, you constructed an argument with documented facts (time, data, action), developed opinions, and then made recommendations flowing from the facts and opinions.
Many organizations develop "best practices" by studying process and results and adopting 'pathways' to encourage adherence to those business plans.
This CoachingToolbox article examined top college defenses and reports how they approached several defensive questions. I'd speculate that most of us try to 1) limit what teams 'like to do', 2) excel at what our personnel and expertise 'allow us to do', and 3) try to keep the ball away from the basket and force opponents to make "hard 2s".
Not surprisingly, the piece addresses:
Force bias
Double-teaming (Traps or in Pete Newell verbiage Two-timing)
Post defensive positioning (three-quarter/fronting)
Ball screens
Core defensive values (no middle, contested shots)
Kevin Eastman refers to much of this as "know your nos" as in what will you absolutely take away and establish in your team defensive identity?