I would say the best way to get this achievement is to keep your tank back far behind you as you clear out the enemies. Do this on the easiest difficulty (Regular) so you don't die as much. If you keep the tank way back behind you, things like RPGs will most likely not hit it. As you move along through the level, you will run across suicide bombers. They will run straight toward the tank and kill themselves, thus dealing damage. Listen to your teammate on the comm station as he will tell you when their are RPGs, Tanks, and Helicopters inbound. Suicide bombers can be noted by the red glow on their chest. Make sure you kill them as fast as you can. Other than that, you will come across around 4 helicopters and two tanks. You can use your own tank to destroy them, but I recommend using your secondary, the SMAW, as it can lock on helicopters, making them easier to hit. If you need ammo, there is an ammo cache on the tank for your use when you need ammo for your SMAW. Other than that, play it safe with the tank and kill all the suicide bombers and RPG troopers as fast as you can to prevent them from hurting the tank. Just make sure you killed everything and slowly move the tank up. Don't rush, as patience is key to this achievement. Good luck!