TankingquestionFollow

You will have to go get him 90% of the time. If you are playing with savvy players and/or guildies you will probably have players who know to bring the mobs back, but don't count on it.
Having said that its always situational - if the mob is near death let it go and build threat on the rest.
Knowing when to react in particular situations comes with experience, which is why its important (IMHO) to tank every instance you can as you are levelling.

Here is probably the best site for tanking info. Its a gold mine, get to know it well.
http://www.theoryspot.com/

Cheers!
Tiq

there's really no such thing as an off-tank in the instances you're running. from the way you asked, it sounds like you're losing one to the healer? definitely taunt off your healer right away. if it's dps, make sure they are following the kill order (which you should be marking).

as far as your instance runs go, first make sure everyone knows to run TOWARDS you if they get agro. second, do a better job keeping up multi-mob threat. add a shield spike and keep thunderclap on cooldown. tab-sunder if that's not enough.