So I am (still) pretty new to tanking (been using DRK to learn it since its been rather easy thus far, I'm only level 51 almost 52 also got level 30 GLD and level 20 MRD) and have hit a point where the tanking has become... not so obvious.
Tanking in 4 man dungeons is in general easy. Initiate from a distance, gather mobs within limits of the capabilities of the healer and the AoE DPS of the party, group mobs for easier AoE. Ensure mobs are rotated from the party. Keep mobs from spinning so positionals are easy for the DPS to do. Obey boss mechanics. Snag adds as they come. Same for 4 man trials.
I've had people call me a good tank, though I do not think the same honestly.
Dungeons and Trials which involve 2 tanks though confuse me.
My first run of Castrum (main story roulette) the PLD asked me to main tank, so I turned on grit and started grabbing mobs and after they got obliterated by the party I told the PLD that I was new to this run as a tank (it was actually only my 2nd time even doing the run in the first place), so he told me he was taking over as main tank.
I proceeded to go "... and what do I do now?" in my head as I followed his lead, turned grit off for the time being, smacking things like a melee DPS, when adds started spawning during a boss fight I would swap on grit and go gather them up. Or I would go run the opposite direction of the main tank and snag mobs on the other side of the splits and drag them to the main tank to add to the AoE pile.
I admitted to the party I had no clue what I was supposed to be doing. Was told I was doing a good job as off-tank despite not having a clue what I should be doing.
I still do not clearly know what I am supposed to be doing in these duo tank dungeons and trials though. I guess in 3 tank raids I could be leading my party as their particular main tank or something?