I think tanking is the friendlier of the two support roles in terms of what you can bring to a run because you're more limited than a healer.
You know your gear is good so beyond that there are a few things you can do to ensure success to the best if your ability.
- 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.
- 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.
- 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.
- 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.
I hope these help out!
If you're doing all that and you still die it's either a healer issue (bad/bad gear/bad connection) or if things are taking absolutely forever to die it might be on the dps. If you and the healer are both doing your basics though you won't be wiping on trash.
(Also I totally should be using Holmgamg probably, I know they buffed the duration forever ago. I will pop it in an emergency just like LD but for some reason in the heat of the moment my brain still thinks of it as a short duration CD. Bleh.)
Other than the worm one which never struck me as particularly impressive you're just listing some of my favorite pulls.
God, that Ala Mhigo one was amazing. My friend was tanking that our first run ever and we had agreed to always go as far as we could to find out what the limits were... so, so spicy. I love it.
