First, the Finns know that aggression affects aggression and does not respond to aggression by aggression.
But there are special methods
1. To teach all citizens from school, to report against each other if they learn about even a petty crime. Reporting is taught at school, but in order to teach people faster, you can connect media and Propaganda. To say how wonderful it is and how it helps the society to live peacefully and pleasantly.
2. The police should be responsive and take not only crimes, but also for simple threats and insults. People should not carry aggression towards other people, otherwise the police will talk to you, and maybe even you will be sent to short courses about how to exist in this society and how your aggression affects the surrounding people. Aggression is bad for society. Everyone becomes angrier and does not trust each other. Appearance appears, and people slope to conflict and begin to defend themselves more often in rough form.
There is another method to fight criminal people from disadvantaged families who regularly confront other people and fall into the category of "problem" people
For this, you use the Marketing tool - Target Marketing.
Seeking ways to influence immediately ALL GROUPS of people from criminal circles. And they replace beliefs through media, propaganda and specially created for them "authorities".
For example, instead of the belief "one must beat first, life is complicated we must survive" we replace with "We must look beyond the area so that people live well and in peace." We simply replace their favorite beliefs "survive" by "defending the area or the city" "so that people quietly and peacefully live" "without fights and crime" "we need to monitor the order" and so on
Do it all through media, propaganda, internet blogging, pictures on the Internet and specially hired actors and musicians who should become their number one authority, and then this actor will say that "a dangerous boy must protect the area so that he lives in peace"