See the links below for more information about community-based tools, theories and strategies that can have the most positive, long-term impact on crime.

Collective Efficacy: 

Crime is lower in neighborhoods where people know each other. Crime is also lower if everyone expects each other to intervene in illegitimate activity.

Crime Prevention through Environmental Design (CPTED, pronounced sep-ted): 

Changes in the urban environment can increase positive activity in high crime areas.