Quick And Easy Good Cop Points:

If you want to earn good cop points quickly, go to a street called Rose Ave. in Venice. All of the people walking on that street are usually either carrying drugs or guns. Simply walk up to anyone on that street and frisk them and you'll bust them. (Rose Ave. is the street by the beach and in directly on the "N" in the title Venice on the map; you can look up the map from the start menu).