Event Planner Complete all of the open world Events.
There are a total of 11 Random (Secret) Events. They include 4 Shoplifter Events, 3 Hit and Run Events, 4 Junk in the Trunk events. Unlike the collectibles or other side missions, the Random Events are the only thing in the game that is not shown on the map. You have to finish those events if you are going for 100% game completion. The events take place at random times, but have fixed locations. You have to make some good progress in the game before the events show up (completing story missions, side missions and favors). The events are not available from the beginning on! Once you are done with the story and side missions you are good to go.
Your best chance to find an active event is during daytime when the weather is sunny. 10am - 2pm works best. The Shoplifter events won't show up at night or while it is raining!
If you think none of the events ever shows up you have to progress further in the story and complete more favors. Don't worry if you messed up during an event. It will respawn later on.
To unlock the Event Planner trophy / achievement you also have to complete all 17 drug busts! Those are shown on the in-game map and are not included in this video.
A Slap in the Face Kill someone with a fish. This can be done during a mission called "Club Bam Bam". It's one of the first couple missions in the game. You can replay it by going to the Social Hub Section in the pause menu. Once you enter the VIP area a bunch of thugs will attack you. Throw one of them into a fish tank. There is a 50% chance that a fish will fall to the ground. Pick it up and punch an enemy with it. There are two other fish tanks in this area and you can restart the checkpoint if you don't get a fish on the first try.
Safe Driver Cruise for 2 minutes straight without damaging your car.
First of all go and get and really slow car with good handling. Slow motorcycles also work quite well. Your car may not sustain any damage during the drive and you have to keep a high speed all over the time. If you get too slow the timer will reset. Just use the freeway at the edge of town and hit the pedal to the metal.
Stuntman Successfully perform an action hijack.
While driving a vehicle hold down X (PS3) / A (Xbox 360) to prepare for an action hijack. You can now see arrow symbols above the cars on your side of the road. Quickly Tap X (PS3) / A (Xbox 360) when the arrow becomes green. If done successfully you will take over the other vehicle.
Infowlable Win 50,000 on a single cockfight.
Go to the cock fighting in Kennedy Town. The minimum bet there is $50.000. Always bet on the rooster that has the most wins. If your rooster wins you will get a total of $100.000.
Note: On Playstation 3 this trophy appears to be glitched (tested with European PEGI version of the game). You actually have to bet $50.000 and win $100.000. Just winning $50.000 won't unlock the trophy.
Sharpshooter Shoot out a cop's tires while fleeing in a police chase.
First of all you will need a weapon. Go to a police station and knock out a cop to pick up his gun. Now hijack a vehicle and shoot the tires of the chasing police cars.