Why I like tanking:
The thing I enjoy most about tanking is that you need to be intuitive. It’s about being able to adapt and anticipate your target’s next move rather than about perfecting your rotation. One badly timed bar swap might be the end of everything. It’s a thrilling experience and a lot of responsibility.
You get to be the cheeky bastard to quite literally poke the dragon in the eye.

Gear:
The trait you want is Sturdy, preferably on all armour pieces. Infused for Weapons.
Jewellery with Shield Play glyphs, weapons Crusher and Weakening enchantments.

You always want to make sure you have a 5 Heavy, 1 Medium, 1 Light Armor-Setup. How you do that is up to you and doesn’t matter all that much. However, if you want to go for the optimum you want to make sure the smallest body pieces possible are you Light/Medium armour slots. With two heavy sets you’ll have to use the Monster Set for you Light/Medium slots but with Alkosh you can go for a medium belt and light shoulders and with Torug’s Pact you can even switch to light belt + medium gloves.

Monster set: Lord Warden
5-Piece-Sets:
Ebon, Plague Doctor, Torug’s Pact, Alkosh (this is a medium set, so you’ll need jewellery and weapons), Green Pact
When to wear what:
Best in Slot for a tank means being able to combine any two of these sets and having them all at hand to switch around as needed. For example, Alkosh is useless if you do not have at least 2-3 synergies (that don’t share a cooldown like Bubbles and Shards) available to you from your group members at all times, plus synergies from ultimates.
In a situation like that Torug’s Pact would be stronger than Alkosh. Same for fights in which those synergies a theoretically available but won’t reach you due to positioning.
For trials as a main tank, you want to be able to combine Ebon + Alkosh if you don’t have an off-tank. With an off-tank using Ebon you can go for Plague Doctor + Alkosh. For dungeons without a Magicka sorcerer, you probably want to use Ebon + Torug’s Pact because you won’t have a high Alkosh uptime. If you go for a trial like Sanctum Ophidia with the main tank just kiting adds in a corner at Ozara, you don’t need to de-buff the mobs with Alkosh or Torug’s Pact - here you can go for a maximum Health setup to make it easier for yourself. For a maximum Health build you go for Plague Doctor and Green Pact, with my attribute points, I reach 50k Health easily.

Consumables:
Buff Food: Tri-Stat-Food
Potions: Magicka Tash Pots, Tri-Pots if the situation gets extreme. Usually you should need hardly any pots though. If you pay attention and block only when you actually need to rather than standing there, perma-blocking and hoping for the best, you shouldn’t have any problems managing your resources, even with the increased block cost since the Dragon Bones Update.

Additional Notes:
A tank can dodge, too, and avoiding hard hitting AOEs as much as you can without moving the target out of the ground abilities of your DDs is always a good idea!
I’d suggest using an Addon like e.g. AlphaGear to coordinate your setups! Otherwise you easily end up not wearing complete sets or missing out on the 5-1-1 bonus because you forgot to switch your Lord Warden Helm with a Lord Warden Mask.