Is there a strategy when playing as a tank in a versus match?

The Tank is arguably the toughest special infected to play. Your team expects you to take down all four survivors on your own, which is next to impossible without help from your teammates. Ignore anyone that calls you a n00b after a failed Tank run. Learn from it and try different strategies next time.

The Boomer will be the biggest help to the Tank, because if he manages to get bile on one or more survivors, a horde of common infected will spawn in to attack (normally they do not when the Tank is around). This helps to distract the survivors so you can go in for some good hits.

Never, ever get yourself caught on fire. If the survivors have Molotov cocktails or gas cans, stay away from them. Don't just rush in and try to beat up on them. Stay back and throw rocks in an area where they can't light you on fire.

Coordinate with your teammates to try and incapacitate survivors long enough for you to get close to them, especially Hunters. If another survivor shoots a Hunter off a survivor, it will take them a few seconds to stand up. That gives you enough time to hit them.

Attack the weaker players first. Don't rely solely on the red, yellow or green outlines of the survivors either. Use the tab menu to see if people have used pills to increase their health higher than the color bracket their aura falls into (a player in the red can have 60+ health after taking pills).

Once you have a survivor incapacitated, do not continue to attack them. The damage dealt to incapacitated survivors is paltry and it will take you ages to kill them that way. Instead, stay nearby incapacitated survivors so that when their teammates try to revive them you can go in and hit them.

Just to add to cowgod's great answer if you're in an open area don't even try to chase survivors, they'll easily keep their distance and shoot the crap out of you at the same time. Also be sure to use cars, bins and forklifts when you can as it will cause instant incap.

Tip: In the Carnival campaign on map 4 if you're a tank, hit the "Test your might" game so it rings the bell and you will call a big horde. Use that to get to the survivors.

Also if you run out of good ideas described above, you may try these.

Run away from the survivors so that they loose track of where you are. Then climb the infected-only ladders to get above their heads. Then just drop on their heads at the right moment. If you get lucky, sometimes you can hit several of them in s single bash. Also if they run in different directions, your teammates will get a good opportunity.

Also if one of the survivors gets incapacitated and there is car or a trash bin nearby, you can try hitting him repeatedly with it. This way you can kill him in a reasonable time and a bottomline of one dead survivor is still better than some damage to all of them.

On the final area use the tanks as artillary with rocks from afar and out of sight but keep the tank under control. That way your allies will ahve more attack time and, if played well can buy time for extra horde attacks.

I've done this tactic before on wide open maps and you can kill the enitre ememy team before the first tank loses any health.