So Umm....

[Nethereal]

Squadron is one of the most cancerous things to tank. The npc healers just aren't as good.

[ReiMakoto]

Find a healer who is willing to be harsh to you and let you live whilst they also dps like made and only heal you when necessary and make them drag you through dungeons. Onces you get used to the fact that your health will go all over the place and the healers got you covered tanking becomes a lot more stress free. (obviously popping CD's is a must too)

[Atlas-04]

This expansion is gonna be flooded with terrible tanks. I'll need to handcuff myself to a my tank friend.

[Kazrah]

When I first started tanking in this game, there was no PotD or HoH, so I picked it up by practicing with fates and open-world mobs. It might not sound like it gives you that "tank" experience, but just going up against open-world stuff teaches you personal survival and helps with rotation practice without the hassle that other players can bear on you.

When you feel comfortable enough to tank dungeons, treat the other players like a programmer would treat end users for their program: expect the absolute worst of humanity. They will be mean, they will be stupid and you're gonna have to be an IRL tank and take any insult with whatever mental tools are at your disposal. I personally recommend apathy, because I'm not going to care if a DPS pulls when it just means that they'll be dead and I get to bounce on their corpse and all will be well in the universe.

[Vahlnir]

This expansion is gonna be flooded with terrible tanks. I'll need to handcuff myself to a my tank friend.

At first, probably. Lots of people will want to try it out. Same thing happened with DRK for a few weeks. When the dust settles most people will go back to their original jobs and things will balance back out. Bad tanks have always existed...it's not a new release exclusive thing.

[Nedkel]

You may want to ask this question in the Tank section of the forum.
People here are throwing some random tips which may not be exactly true in all sorts of situations or duties.

I recommend you to watch this
https://www.youtube.com/watch?v=0fS-FVrY74Y
and this
https://www.youtube.com/watch?v=BDnGQkRNmAw

[SenorPatty]

If you wanna go straight into the action, start "mid-low". Bray-flox and Haukke Manor are ideal for first time tanking. You're not gonna be mass pulling anything there so you can take your time and do the groups one after the other. Once you're comfy with that, move onto the challenging ones like Dzamel Darkhold and Aurum Vale. These two will teach you positioning and zoning. Once you're good with that, you'll want to further your training by looking up indepth guides and getting more lessons with lvl 50 or 60 24man raids as well as early lvl 70 8mans.

[Gemina]

What's the best way to somewhat "maybe" get into tanking? ><

If you're just getting into it, the first steps are definitely Ul'dah >> unlock Gladiator >> get it to lv15 while understanding your tooltips >> hall of novice for some practice and to obtain some really good starting gear >> take a couple of deep breaths >> queue into Sastasha.

GG's tanking guides provided by the previous poster are really good guides. The principles you learn about tanking that you learn early on apply to the max level duties as well, so the sooner you get these down the better off you'll be, and you'll be a cut above the average PUG tank that is for sure.

[AxlStream]

My tanks are lvl 70. I prefer PLD as that's the only one that "feels" like a tank wither their sword and shield. I'm mostly just not sure on some things like, during a boss fight should you be cycling through your defensive cool downs on cool down or waiting to use them for a tank buster / party AoE? Also how do you recognize a tank buster if you've never seen the fight before?

Tank mains just know when something like a tankbuster comes up, even if they've never seen it before. It's a 6th sense.

[Dirwen]

I have all three tanks done but WAR probably the easiest to start with if getting into the tank role. War feels like a DPS kinda is why as it gets a very strong aoe that does decent dmg and gains hate and it's available at low level.

As for pure tanking? I think PLD is the best when mitigating damage when it gets to level 60 and up.

DRK was my least favorite tanking job to level it felt more complicated to play compared to WAR/PLD. Only reason I bothered was for the cool glamour.