I work hard of maintaining the ability to walk up and talk to anyone. If I feel put off by someone, or some group, I often make a point of walking up to them and talking. A smile and open hand go a long way toward humanizing yourself to people who judge you, and you them. Demonstrating that your not afraid of them, even if you are, and they have no reason to be afraid of you, even if they do, is the basis of all diplomacy.
Diplomacy is all about respect and admitting that both sides have a right to be there, a right to be who they are, and everyone has legitimate interests and concerns. Once you establish that you establish that neither side is going anywhere so everyone has to deal. Then it is just cutting a deal.
A big step is to realize that aggression and anger mostly come from fear. That the burning desire to stock up on weapons and ammunition is a not an expression of strength so much as an expression of weakness and fear. You don't want to start off declaring that but it goes a long way toward understanding people.