I know that tanking Kz with a starting guild and some blue/epics as a tank can be a real pain in the ass.I hope this thread is usefull.
First of all you need to make clear to the raid to give you some time to build aggro and not to start DPS cause you will lose your aggro fast as hell
Spam devastate and shield slam remember that 5 devastates give more threat than sudden armor.
importand thing to remember is that always before pulling you will need to get your rage up so you can start threat at once and not delaying the dps until you have the rage to build aggro
in tanking multiple targets thunder clap is the most effective way to keep your aggro up on all targets.try to taunt(when available in kz cause many mobs and bosses are immune to taunt in kz :S )one target all the time and devastate and thunderclap the other mobs one by one.
inervene is a very usefull ability when you are just starting tanking raids cause probably some1 is going to overaggro you remember to keep an eye on healers and aoe cloths.
also very nice ability in Kz is Mocking Blow cause as i said many mobs are immune to taunt and that makes a prot.warrior life harder
try to make the healer life easier with shield block/demorilising shout/pots/disarm and concussion blow.
for addons deadly boss is a MUST and omen for start.
Starting Requirements are 490/500 defence and 11k/12k hp unbuffed personaly for starting tank i would recoment to have more dodge than other defences.with that you will make the healers life easier and that is very important for starting kara.
i hope this helps...if i forgot something tell me about it