1. Miscellaneous
1.1. Tread Lightly – Liberate any Outpost without triggering an alarm
1.2. From A Distance – Kill a target from 60m or more with an arrow or bolt
1.3. Two Birds – Using a sniper rifle, kill 2 targets with a single shot
1.4. Quad Kill – Kill 4 enemies simultaneously with a single explosion
1.5. Custom-Fitted – Buy all attachments and paint schemes for a single weapon
1.6. Changing Lanes – Perform a Vehicle Takedown from the passenger seat of a vehicle
1.7. The Sky Is Falling – Perform a takedown from a Buzzer

Tread Lightly
Liberate any Outpost without triggering an alarm in any mode (Campaign only).
There are a total of 24 Outposts. You can liberate any of them without triggering an alarm. Search for the alarm switch in an Outpost and disable it by pressing Square (PlayStation) / X (Xbox). Now you just need to kill the remaining enemies. It does not matter if the enemies see you or not. They are just not allowed to ring the alarm. If you hear the alarm then kill yourself and you should respawn somewhere near the Outpost and can try it again.
It works best on the easy Outposts near the beginning of the game because they only have one alarm switch. Kyra Tea Weigh Station (coordinates X: 344.5, Y: 379.0) is great for this!

If you’ve already liberated this Outpost you can replay it any time via the “Outpost Master” icon on your world map.

From A Distance
Kill a target from 60m or more with an arrow or bolt (Campaign only).
First of all you should buy the Recurve Bow from a weapon locker. Also buy and equip the Marksman Sight. It’s a very useful attachment for long range shots. Now search for some enemies and put a marker on their location on the world map. Walk away until the marker shows a distance of 60+ meters and take the shot while the enemy is standing still. The Rochan Brick Co. Shipping Outpost (coordinates X: 393.6, Y: 503.6) is near the starting area of the game and one of the best locations to get this done early. There are two enemies out in the open, standing completely still.
If you’ve already liberated this Outpost you can replay it any time via the “Outpost Master” icon on your world map.

Two Birds
Using a sniper rifle, kill 2 targets with a single shot (Campaign only).
This can easily be done at the Rochan Brick Co. Shipping Outpost (coordinates X: 393.7, Y: 503.5). There are two enemies standing right next to each other. They are standing completely still and are easy targets.
Buy a sniper rifle and get close to them, but avoid being detected. Now when they are perfectly lined up you shoot them both in the head. Most enemies in the game have body armor and shots to the torso won’t kill them. So make sure you do a headshot.
If you miss your shot or only kill one enemy, then get yourself killed and you will respawn at the outpost again. If you’ve already liberated this Outpost you can replay it any time via the “Outpost Master” icon on your world map.

Quad Kill
Kill 4 enemies simultaneously with a single explosion (Campaign only).
To do this you will need to buy an explosive weapon. The RPG-7 works best (costs 160,000 Kyrad Dollars). Now go to the Rochan Brick Co. Storage Outpost (coordinates X: 440.4, Y: 543.0) and set off the alarm. Wait for the reinforcement cars to arrive. In the car without a turret are 4 soldiers. Shoot this vehicle with your rocket launcher before the soldiers get out. Alternatively you can also plant some C4 and group up some enemies, then blow it up. If it doesn’t work on your first try, then simply get yourself killed and you should respawn somewhere around the Outpost and can try it again.

If you’ve already liberated this Outpost you can replay it any time via the “Outpost Master” icon on your world map.

Custom-Fitted
Buy all attachments and paint schemes for a single weapon (Campaign only).
For this trophy / achievement you will need 200,000 Kyrat Dollars. Money is very easy to get in this game. Just loot some corpses or open loot chest and you will have enough money within a couple of minutes.
Now go to a weapon locker or merchant and select a weapon that doesn’t have any attachments, for example the AK-47. You will only need to buy the 6 paint schemes. The weapons that don’t have any attachments are the cheapest option.

Changing Lanes
Perform a Vehicle Takedown from the passenger seat of a vehicle (Campaign Co-op only).
For this trophy / achievement you must buy the “Vehicle Takedown” skill and play together with a friend in Co-Op. With the skill equipped you must be on the passenger seat while your friend is driving the car. Your friend has to pull up to an enemy vehicle and then you need to press the right stick to perform the takedown.
It’s slightly random where enemy vehicles are spawning. They spawn most frequently around enemy fortresses and outposts, but there are lots of random convoys too. Alternatively you can do it in the reinforcement wave of an outpost. Let the guards activate the alarm and some reinfocement vehicles will come in.

The Sky Is Falling
Perform a takedown from a Buzzer (Campaign only).
To do this you must buy the “Vehicle Takedown” skill! Now get into a Buzzer (small helicopter). One can be found at the first outpost in the game which is called “Khilana Bazaar” (coordinates X: 305.0, Y: 422.8). You have to search for an enemy vehicle or convoy. They spawn most frequently around hostile outposts and fortresses. There are lots of convoys between the Kyrat International Airport and Noore’s Fort in the western corner of the map.
Fly next to the driver’s door and press R3 / the right stick to perform the takedown. This only works as long as there’s a driver in the vehicle.

Beware that there is another skill called “Death from Above” that lets you perform a takedown when jumping / falling onto an enemy. Doing such a takedown will not give you this trophy or achievement! It has to be a vehicle takedown!