We can only start with ourselves. We're not immune. No one is
  immune. But on a societal level: media.

  In theory, one could regulate media against bias. But too much
  of that and there's a backlash, and the built up pressure of
  conformity bursts forth.

  Some children growing up today will become police officers.
  That's the place to start. Many efforts have gone on for many
  years in cartoons, education, etc. But then you have parents.
  Then you have grandparents. Then you have neighbors.

  And there's the forbidden fruit. Things you can't talk about.
  Things you can't say. It's an irresistible pull and can burst
  forth.

  So beyond training when young, how do you handle police of 2015
  rather than the police of 2040?

  Psychological training is one.

  Another is returning to the old ways before cops were allowed to
  defend themselves with a bullet. [I believe that's pre-1990. A
  ruling went forth that made 'shoot first' acceptable in a more
  broad amount of cases, due to a very bad case of a policeman
  being shot.. I don't remember the case offhand but I can look it
  up].

  I'd advocate police use shields instead of guns or alternative
  guns.

  Think about it; What defenses does a policeman have? Primarily?
  The gun or a loud voice from a distance, handcuffs or physical
  restraint from close up.

  Not much else.

  I think that should change.   Oh I believe that good cops
  outnumber bad cops.
  Good cops make boring news.
  We want to see bad cops and that's what they give us.
  But still, something has to change for the better.