As I have seen, telling people what to (not) do, even with causal awareness, is not very effective, unless you dispose of multiples occasion on a large lapse of time where you can repeat important concepts multiple times. This because of how our brain learns.

Probably an optimal method would be to explain in schools principles about anthropology, sociology and psychology, in particular the logic behind development of social groups and how this are involved into inclusion-exclusion patterns, even in the natural kingdom.

To improve our collective and individual behaviors, we all have to start studying and analyzing generic human (and our own) behaviors in the same way in which we study all the other fields of human knowledge as physics, music or sports.
This include listening and reading educational material (even podcasts or blogs) from experts in each field. In this case are behavioral scientists, psychologists, sociologists and so on.