There's been a lot of talk about warriors not knowing how to tank, so this is my take on how to tank in an instance. All constructive criticism is welcome, all flames will be replied to with a "well write your own guide then" so save both of us some time and don't bother.
I'll be thinking mainly about 5 man instance groups, although a lot is still more than relevant in the raid instances, what you learn at low level will see you through to molten core with ease.
I'm not going to go into tanking talent builds, as my views are that 31/20 is just as good as any other and that prot isn't needed it just helps a little, I'm just going to cover the absolute basics that will give people a good basis for them to start on. However, I do make a few assumptions, mainly that you have tactical mastery, which if you don't, you will need to go and get. You cannot tank without it. Actually, you cannot do anything as a warrior without it. (well, you can, just not efficiently)
Firstly, we have the 3 most important aspects of tanking.
1 - First and foremost, use a shield!
This may seem like a given, but you'd be surprised at how many people try to tank with a 2 hander. The excuses for this range from "I do more damage like this" "I don't have a shield/one hander" or "I generate more threat with a 2 hander". All of these are rubbish. Firstly, you are a tank, not a rogue or mage, you're not there to do damage. If you don't have a shield or a one hander then do not try to be main tank. As for generating more threat, that's the worst excuse as shield bash generates way more than any attack with a 2 hander will, and as the name suggests, it needs a shield.
The main reason why you should always use a shield is the damage reduction. A priest will have a hard time keeping up with the heals if you insist on using a 2 hander. At 60 my shield adds around 12% extra damage reduction.
Secondly, revenge, I'll cover this skill in more detail later, but needless to say shield = block = revenge.
(I know that when you're a pr0 ub3r tank you can use a 2-hander and think you're just as good as anyone else, but really, you're not. Lets leave it at that and no "I cn tnk wid a 2hndr" posts please)
2 - Be defensive!
Defensive stance is a must. Not only does it reduce the damage taken by 10%, it also generates additional threat, and has a few nice abilities that are great for holding agro. I've grouped with many warriors that refuse to tank in defensive stance, to them the 10% less damage they give is more important than the 10% less damage they take. These are bad warriors. Most of your time should be spent in defensive stance. As a general rule, if you can do it in defensive stance, then do it in defensive stance. This goes for everything from sunder armor to demo shout. While it may not be much doing these in defensive stance adds extra threat that makes it harder for you to lose agro.
3 - Protect your priest.
If something is beating down on your priest, get it off them, your sole job when your priest is losing health is to get whatever mob is on them off them and onto you. If the priest goes down, you go down. The ways of doing this vary greatly, and depending on the situation. If your priest is close you can just switch target, taunt and then build agro on that mob until you're sure it's on you. If your priest is far away your main goal is to get to them as soon as possible. My favoured technique is to switch to berserker stance, intercept, then back to defensive and taunt. If there are multiple mobs on your priest you're going to want to follow this with a battle stance, mocking blow, or in worse situations, challenging shout.
As a warrior your priest will be relying on you to keep them free from agro, just as you will be relying on them for healing. If they have agro, you can't be healed.
Once you know the 3 basics you have the foundation of knowledge you need to enter the world of a tank. However, that's just the beginning.
There are 3 stages in tanking that you'll encounter, each of these is as important as the next, and to be a complete tank you will have to master them all.
Getting initial agro
There is nothing more important than getting initial agro on a group of mobs, without agro you gain less rage, which makes it harder to get agro. It's a viscous circle that basically means that a bad start can mean a bad finish.
-Start with a charge if you can - This doesn't just give you rage, it has a stun chance, which = threat. If you can't start with a charge (like if you have to pull mobs towards you) then blood rage is a good skill for getting you some much needed rage to start throwing out the agro building moves.
-Follow up with a demo shout - This doesn't just reduce their attack power, it allows you to get a little agro on each of the mobs so they are less likely to take an immediate interest in your priest.
-Try to fit in a Whirlwind - don't overlook this skill. It may be in berserker stance, but attacking 4 mobs = threat on 4 mobs.
This should take around 5 seconds, and then and only then should the rest of the group attack.
Threat building
Once you have the initial agro on each of the mobs you're going to want to keep increasing your threat so as none of them come off you and attack someone else. Luckily as a warrior you have several key skills that are useful for building threat.
Sunder armor,
Revenge,
Shield bash,
Disarm.
These are the 4 key agro building tools you have available to you, and you should have everyone on your hotbar in easy to use positions.
Sunder is our spammable skill that builds a fair bit of threat, you'll find yourself using this a lot as it has a low rage cost, and builds a nice amount of threat. All the mobs that you are tanking should have sunder on them.
Revenge is a great skill that builds a lot of threat. It can only be used after you dodge, block or parry, but after a couple of revenges Ragnaros himself won’t be able to pull a mob from you. This should always be used on the main target when it's available. It'll make them stick to you like glue.
Shield bash doesn't just interrupt spell casting, it makes them hate you as well! It builds threat on non-casters just as well as casters. This is another skill that you should be using mainly on the main target; it'll keep them on you even when you're building up threat on the other mobs.
Disarm is great for reducing the amount of damage you take, but also for building threat. There's a lot of mortal strike speced mobs out there, and we all know how nasty mortal strike is, disarming them stops them from using it on you, and also makes them hate you for it.
To make sure you keep enough agro on the main target you need to spend most of your time building threat on that. However, you cannot ignore the rest of the mobs.
Between each threat building attack on each of the mobs not being attacked, you should do at least one on the main target. That means no matter how many mobs are on you, you still spend half your time making sure you can keep the main target on you, and the other half building threat on the others to ensure your priest doesn't pull agro with a heal.
You may be wondering how you'll keep track of which mobs you've been building agro on and which you've let slip. For this I recommend the sunderthis add-on. It allows you to show the currently sundered value above a mobs target box. That way if every time you cycle through a mob to build agro on it you sunder you can keep a count on which mobs have had more of your time than others, and keep your threat level pretty even on each of them.
Getting back the agro
At some stage or another, either through a trigger happy mage, gung-ho rogue, or you not having enough threat to cover that big heal from the priest (it's never the priests fault, if the priest gets agro, it's your fault), you will lose agro. It's no big deal, as long as you know how to get it back.
The obvious choice here is taunt. It does exactly what it says on the tooltip and makes them attack you again. If it's just one mob that turned away then all well and good, a quick taunt and back to threat building we go.
However if things have gone more wrong than that you may need to draw on a couple of other skills.
-Mocking blow, in battle stance forces a mob to attack you for 6 seconds, just enough time for you to get off a few sunders, maybe a revenge, and a shield bash.
-Challenging shout makes all mobs attack you for 6 seconds, in which time you'll need to cycle through all of them and fire off those sunders.
-Or, in the worst possible situation, where everything has gone wrong and it looks like nothing will get all the mobs on you, we have the patent pending "oh !&$%, everything’s gone to $!@%" method of getting agro back, the one chance only, no turning back, uber threat building combination of… challenging shout retaliation! That's right folks, if things go wrong we don't go down without a fight, warriors never say die, back against the wall, or a corners even better (we don't want any attacks from behind now) and hit challenging shout… then retaliation, then sit back and watch the numbers fly, and imagine your threat level skyrocketing. If that doesn't save your group from a wipe on a bad pull when your cloth wearers are all taking hits then nothing will. (try not to make a habit of that though… at once every half hour it's not really a spammable tactic)
Main Assists
A lot of people seem to have the idea that the main tank should also be the main assist, the guy everyone assists to find the mob that people should do damage to. This isn't true, in fact this is probably the worst way of doing things.
The main tank and the main assist should always be 2 different people, generally a damage dealer should play the part of main assist.
This is due to the fact that as a tank you will never be targeting the same mob all the time. You will need to constant rotate between each of the mobs on you to keep building threat on each of them. If you sit there attacking the one mob that everyone is attacking as soon as a heal goes on every one of the other mobs will run straight at your priest, and remember what we said about protecting your priest? And if you're acting as main assist as a tank then people could have a different target depending on when they decided to assist you, and there's nothing worse than trying to keep 2 mobs on you that are being spammed with high damage attacks.
The way that I find a lot easier is if one of the other members of the party is the main assist, and everyone has their assist macros set to them even you) This way you wont have your party complaining that you keep switching target and they don't know who to attack.
Pulling
Always pull.
This is one of the most important parts of tanking. Pulling means that the mobs will initially target you, it's easier for you to build agro if they are already attacking you rather than having to pull them off someone else. You will get to learn when and how to pull.
The other main benefit of you pulling is that in the worst case scenario, when a pull goes bad, when you pull the entire room because you didn't see the patrol and you have 10 mobs beating into you, you can die alone. It will save you from a wipe. However, make sure your group knows this is the case, you don't want your priest healing you on a really bad pull and the whole group having to go down. Making a macro to say something like "bad pull DO NOT heal or attack" to warn your group of a really bad pull will save lives.
When and where to pull
Always spend a moment to look for any patrols.
Only when you are sure that there are no patrols should you consider pulling.
Only pull things that have a clear path towards you. This is really a no-brainer, but pulling through other mobs pulls them too.
Always try to pull around a corner. This stops any ranged mobs from staying ranged on you, they will lose line of sight so will have to come into your melee range.
Learn the patterns. There is always a pattern. Learning it makes your job a lot easier, if you know when and where each patrol will be coming, you know when to pull each group, or when to wait and pull the patrol instead.
You and your ranged weapon
Get the fastest weapon you can, damage is irrelevant, stats are nice but not needed.
Get to know your ranged weapon, this may sound strange, but you need to know how long it takes from you hitting the button, to it actually firing. Nothing is worse than hitting fire at that perfect pulling position, then having to wait for your bow to fire by which time that nasty patrol is back down this end of the room right next to the group you were trying to pull. Knowing your firing speed can be the difference between pulling a group of mobs, and pulling a group of mobs plus a patrol.
Group Leadership
It's easier as a whole if you take control of the group. You are the one that should always be first into a fight, so you are the one that should decide when and how that fight happens. Many a time you will encounter people who want to be in command. People who will want to pull, don't let them.
The most important aspect of being a tank is being able to control your group. You need them to follow your lead, otherwise things will go wrong. Once you have ran an instance a couple of times you will be in a lot better position to lead than anyone else, use this to your advantage.
You should be responsible for calling the shots, if you want a sap you should say, if you want a shackle or sheep pull, you should call it. However don't think that just because you are ready the rest of the group is. We have no downtime, we can keep up with the Duracell bunny, and unfortunately your casters can't. It's paramount that you keep an eye on your casters mana bars. If it's empty then you're on your own, and we all know how well a warrior does against multiple elites with no healing. Always make sure that no one is sat down drinking when you go off to pull the next group of mobs.
And that's about it. I'm sure there are some things that I've missed, but that's all I have for now as it's nearly 4am. Feel free to comment about anything or add to this with your own tanking tips.
Note on sunder - Alot of people have been saying it's been stealth nerfed to generate less threat, I haven't noticed this, I generally don't need to spam it more than 5 times on a mob to hold agro anyway, and as such it is still working well for me.
