Intro to Tanking

I realize it's rather presumptuous for a Shaman to be writing an article on tanking, but it's my blog and I can write what I want to I've learned a few things in the past few months with my frosty Death Knight tank, and hopefully some of this info will help those taking a look at the noble art of meat-shielding.

Basic Stats
So you've dinged level-cap with your new tank and are ready to tackle some heroics and perhaps even dive into raiding. Congrats! Now there are lots of talent-selection and gear-list websites out there on the interwebs, so I'll avoid going into specifics there - but let's take a look at the basic tank stats: your defense, health, and offense.

Defense rating is what keeps you from getting critically hit, which is hugely important for survivability. At level 80, you need 535 minimum for heroics and 540 for raids. There is benefit to stacking defense beyond 540 as it affects other damage mitigation stats like dodge, etc., but generally after 540 you'll also want to look at your overall health:

Stamina translates to your health pool of course, and the rule of thumb here is the more, the better. Each class has a varying number of health needed (for example, Bears need more than Prot Warriors since they have fur rather than shields), but as a rule of thumb, somewhere in the mid-20k's is a decent number to start running heroic dungeons at level 80. I believe my DK started heroics around 23k (unbuffed) and after seeing all of Naxx, is just shy of 30k.

Threat - they say "the best defense is a strong offense," and tanks are no exception here, as being able to output a healthy amount of damage helps to ensure the bad guys are focused on you, and not your party-mates. Offensive stats like Strength, Hit and Expertise are important in this regard - but again, YMMV according to class so be aware of which stats are needed to generate the most threat.

Don't be shy to enchant your blue (or even green) quality gear - both Enchanting and Jewelcrafting offer "budget" versions of endgame buffs that can help push your stats to a better place. My rule of thumb: everything enchanted and gemmed, always. There's really no excuse to slack here, as everyone in your party/raid are depending on your survivability.

So now you're all geared-up and ready to go. Let's take a look at a few classic encounters and how your tanking abilities come into play:

Marking
In this day and age of "burning everything in sight" with AoE, painstakingly marking each and every mob for kill order and CC assignments may not be as necessary as it once was, but it's still a good idea to at least mark the first and second targets so everyone starts off on the same page. Skull and X are most typically used, and I recommend making keybindings for all the marks - I use the function keys, so I can hit F1, F2, then pull.

Typically, you'll want to mark healers and casters as first targets, but if you're not sure who's who, look for clues in their names like "Spiritualist" or "Cleric." Mana bars are also a good clue.

Line of Sight
Doorways and Hallways are a tank's second best friend. (First are our healers, of course!) For tricky pulls involving ranged or caster mobs, instruct your group to stand behind the corner so you can make an attack then retreat to where they are. If done right, you can reliably pull an entire group, casters and all, right to you. Have an AoE threat ability ready-to-go when they all reach you.

The Big Picture
So you've executed the pull and the angry mobs are all happily beating on you - great job! But wait, half a second later one of the baddies makes a beeline for your healer! What to do?!

First, let's back up a second and understand that it's important for the tank to be aware of The Big Picture at all times. This means putting your toon, camera zoom and angle in a position such that you can actually see what's going on around you at all times. Pro tip: type this into your chat window to increase the zoom-out distance: /script SetCVar("cameraDistanceMax",50)

Taunt
So now back to our pull and the loose mob... which by now has started wailing on your healer - it's time to use one of your most important tank tools: the taunt. Each class has a few ways to do this (some single-target, some are multi-target), so be familiar with each method, and when to use which. You'll also want them hotkeyed for quick action! /cast [Insert Your Taunt Here] and phew, that loose mob is back on you.

Cooldowns
After burning through a few packs of trash, you've finally arrived at the boss. This big intimidating creature is really nothing but a loot piñata, so it's time to go collect your lootz. Let's assume that we're in Nexus, and we're staring up at the dragon Keristrasza. /gulp

This particular dragon has a very common ability known as a "soft enrage," where at low health the boss actually gets tougher. (Life's not fair, even in WoW!) Your healer's doing their best, pumping out heals, keeping the party alive and whatnot, but yikes the boss just turned red and hitting faster/harder now. To make things worse, your healer gets knocked out of range and is scrambling to get back to you. Oh noes!

Luckily, you don't just have to stand there and take it ("thank you sir may I have another?!"), you have defensive cooldowns! Every tank class has 'em: some way to mitigate damage for a short period of time. Shield Wall, Icebound Fortitude, Bubble, etc. As a tank you'll also likely have trinkets with handy on-use abilities, like increased dodge or whatnot - so keep all these emergency buttons close, and be prepared to use them often (albeit judiciously). These abilities can and will save your life, so use them!

Practice Makes Perfect
Putting all this stuff together really takes some practice, so don't get discouraged - everyone has a messy pull every now and again. :) Also realize that tanking is highly reliant on the other roles in your group doing the right things, so group with guildies/friends before diving into the highly unpredicatble world of PUGs. Try running dungeons in normal mode first to get a sense of the encounters and pulls before going in heroic mode.

Further Research
I can't recommend Tankspot enough for their highly informative forums and videos on YouTube. As usual, Elitist Jerks have a wealth of information surrounding gear, specs, etc. While learning boss encounters, Wowwiki and Wowhead are great tools.

Happy tanking!