The toxicity starting to happen.

[tdb]

Make sure you've got threat. If a healer is getting punched they may get interrupted, if that's during a crucial GCD heal it might mean death. You can also try to aim enemies away from your party/healers specifically but this can be hard with WHM and SCH since they should be centered in the pack for their AoEs.

That's a given. I mean, holding threat is the entire point of being a tank. Sometimes I might not hit everything with my AoEs while pulling but I'll gather any stragglers when I get to the kill position. Aggro ripping occasionally happens but I generally notice and correct the situation quickly. And it's usually a DPS ripping aggro when I've switched to single target but am attacking a different mob.

Aiming the enemies away from the party is not always easy due to dodging attacks and large packs of enemies tending to surround me, but I do it when I can. Also I try to not move the enemies around too much if I have melee dps. Unless there's fire on the ground in which case I try to move them so the melee can safely attack them.

Don't take avoidable damage. The simple part is avoiding the bad stuff on the ground (which can really chunk you!) but this can also mean using Interject appropriately (the frogs in the level 73 dungeon come to mind,the empower other enemies if not silenced) and stunning if you don't have a WHM. You can stun an enemy to cancel a ground AoE but you can also just stun an enemy when it's not casting anything to make it lose a few auto attacks. Every bit helps.

I do my best to avoid AoEs, though it can result in some crazy running around if the entire pack of mobs is doing AoEs (a couple of pulls in Sohm Al come to mind, as well as pretty much the entire Heroes Gauntlet). If I know a particular enemy is doing something worth interrupting, I'll prepare to interrupt it by keeping that enemy targeted. It takes some time to learn what to interrupt in each dungeon though. I wasn't aware of the Fuath's buff before seeing it mentioned a couple times recently. I don't remember offhand what its cast time is; in some cases I've noticed an enemy using an interruptable ability but it's like a half second cast so I have no realistic chance to interrupt it.

Rotate CDs properly. This can vary by tank. I don't use Holmgang or LD in dungeons much personally, not unless I know the healer, but HG and Bolide are great to get on CD fast. From there I walk back through your 2min bigboi CDs (Vengance/Sentinel/Nebula/Shadow Wall) and then break into smaller things. If you have a WHM give them a chance to Holy, no need to waste a big CD when the enemies are going to be doing nothing for like 10 seconds of it. Feel free to use your party mitigation too if appropriate, many of them also benefit you. Don't forget about Arm's Length and Reprisal! They're godly on trash now.

This is the part I'm most uncertain about. Nebula, Rampart and Camouflage have long enough cooldowns that they're only available on every other pull. So I figure I shouldn't use all of them on the same pull. Reprisal and Heart of Stone can be used on every pull, HoS often even twice, so I'm using those as filler after the bigger CDs have been spent (at which point the mobs have hopefully been thinned out).

I hadn't noticed that Arm's Length also gives slow to enemies. Now I have to find a place for it on my quickbars which are already too full.

Superbolide is a difficult one since it sets my HP to 1. I definitely don't want to use it from near full health since that just creates extra work for the healer. But if I try to save it for an emergency I may end up using it too late and die anyway. It's honestly the most disappointing of all the invuln abilities due to the self-damage. At least Holmgang and Living Dead can be safely used just in case, even if they can't come close to the OPness of Hallowed Ground.

Access damage and healing effects to the best of your ability. Keep enemies in Doton when you can, make sure you're within the range of Asylum/Earthly Star/Sacred Soil. I've been counting on my big Star pop to save a tank before only to watch him step out at the last second, it feels awful since sometimes there's nothing you can do.

Yeah, there's so many tanks who just ignore Eartly Star in particular. It doesn't help that the sparkling ring near ground is much less noticeable than the huge domes of Asylym and Sacred Soil. If I see any area effects from my party I try to move myself and/or the enemies to them as appropriate (or not move away from them if I'm already in). Enemy AoEs happen though so sometimes I'm forced to move away at just the wrong moment.

Edit: Added some things.