So, in conclusion, Pinker's book is very important and can be broadly applied not only to understanding and working towards continued reductions in violence, but these ideas can be useful in developing healthier psychological strategies in daily life.
These principles include:
1) continued education, to bolster reason, cross-cultural understanding, communication skills, empathy, historical knowledge, and even economics and statistics (these latter subjects can help combat cognitive biases which impede clear understanding of information pertaining to daily living)
2) foster trade instead of fostering war. In some recent news examples, this may not be reasonable (e.g. with some extremely violent groups), but at the very least, fostering trade with adjacent communities would be useful to form alliances.
3) exercise and strive for freedom of speech
4) expand our circles of empathy, to include those in other groups, cultures, and situations. Ultimately, a global issue is to include the environment itself in our circle of empathy. In depressive states, one may be directing aggressive thoughts or actions towards oneself. So the circle of empathy should deliberately also focus on including oneself.
5) be aware of cognitive biases, such as overconfidence in the setting of conflict, underestimation of the risks of conflict, the tendency to deliver vengeful retaliations that would be considered excessive by a neutral observer, and to overestimate the malevolence of an opponent's motives. This could be applied to an analysis about one's own depressive thoughts about oneself.
6) avail oneself of mediators or peacekeepers (this can be a role of a therapist).
7) move away from authoritarian or tribalist practices or beliefs, and instead focus on inclusiveness, individual rights, and fairness. For those involved in religion, work toward a more inclusive, peacemaking, ecumenical, humble theology, with room to include modern scientific findings pertinent to morality, fairness, cultural understanding, and justice.
8) strive for dignity rather than honour
9) work on ways to improve self-control. This does not mean a renunciation of Dionysian enjoyments, but rather it means never allowing one's impulses or habits or enjoyments to cause harm or to rule one's life.