Easy "One Man Army" Trophy:

First make sure you at least didn't unlock all islands yet. It better to have none unlocked because it's faster! First find a rare or super fast car, for example a Comet. Go to the Algongin Bridge and shoot a cop and drive fast to hit the lane, AKA "The Stunt Jump". Hide under the bridge in the middle so you can get 6 stars. Try to stay in a car because some cops jump and will try to shoot you. In that case drive into the subway and hide. Try not go get shot!