The Ruben's guide for APC succesfull trolling:
Apcs are one of the most effective vehicle in BFP4F; good armour, lot of firepower and good speed/mobility.
OMAN:
-Russian side:
Here is all about trollcamping. Nice camping spots are near C where you can conceal most of the apc behind walls while still being able to fire the turret gun. Facing the carrier you can find low walls on the left of C. From there you can pound everything moves from A, or D.
Beware if enemy USA conquers C as some engineer could sneak behind you, as soon as you see that C is lost you can quickly go there and pound the attackers that wont espect it.
From there you can also down helicopters and with some luck even airplanes.
-USA side:
At the beginning dont rush to A, friendly helis will be faster than you and you will not be exposed to bombing and mi 28 fire.
Stay in the water just 50 meters from the shore, you will down easily the unsuspecting mi28 that rush to A and with luck also the mig29 that bombs A.
When Usa conquers A it's time to move. Trollcamping spots are... all over the beach! There are a lot of low walls/barriers that let you conceal the apc chassis while still firing the gun. I personally like the small street just outside A. Placing apc there and going up and down the street i can pound easily B and D and can take shots to the AA gun of C. And in this way i prevent A to be overrun by attackers, so team can focus on conquering.
KARKRRAKAHAND
Russian and USA sides:
Here every corner is good. Try to place yourself on the "flank" of the flow of the game: people will tend to attack in a "vertical" pattern. From USA or Russia base they will attack going "vertical", they will not expect attack from the flank.
GENERAL guide:
APC, and tank also, are not invincible machines. Enemy engineers, other armor and helicopters are dangerous enemys.
So it's always best to hide behind a corner, a wall or a barrier then come out take the shot and go back behind safe cover.
Always keep an escape route and practice reverse driving when you have to rush to a safe place to repair your vehicle (you are not an engineer? Sorry you will die soon.) Smoke is your friend (default "x" key). when you take hit from unknow source or someone traced you pop smoke and escape as fast as you can!
Apc's are formidable against helicopters, shots have a high speed so with a litle practice is easy to hit even long distance tergets, and if heli comes straight toward you you can use also your powerful tow missile.
Same apply for enemy airplanes, more difficult to hit but more vulnerable also.
Remember that trollcamping is not for your own personal kill ratio. It's a way to use effectively the apc. Your goal (Oman) is to destroy as many vehicles you can while on karkand preventing the advancing of the enemy and provide cover for your team attack. And always always use the "q" key to spot enemies. ALWAYS and CONTINUOUSLY it's very helpful for teammates.
So here is the guide, i think i have forget something for sure in case i will wrote down other tips.
Sorry for the long read nad my bad english and happy apc hunting!