Anti-tank tips:

Only use your firearm in extremly short range situations. Otherwise, practice on taking out everything, including infantry, with the anti-tank rocket.

Base anti-tank carbines are okay but the unlocks are vast improvements. I prefer the P-90, which is denied to me in Special Forces because EA sucks.

Vehicle vulnerabilities:

ATVs go down in one hit, if you hit them. I cannot count the number of times I have had a rocket go right through an ATV.

The buggies go down with one anti-tank hit anywhere.

The APCs take two to three solid hits to the back or three to the side.

Tanks are tough. They usually take three hits to the back to kill. It seems to me they are slightly more vulnerable at the junction between turret and body.