First, let's start off by talking about tanking in a general term.
Tanking means that you are protecting your allies from harm.
This assumes that you are holding aggro on the mobs and that you are not dying.
As a tank you are more worried about stats such as Stamina(health), dodge, parry, block, and hit(so you can retain aggro), rather than the DPS stats such as INT or Spell Power.
Most of your skills are used to take less damage, gain more threat than your allies, and deal damage.
Generating Threat As a tankadin, you have a large variety of holy spells at your disposal.
You have two ways to aggro a mob onto you in the form of Hand of Reckoning and Righteous Defense, also you deal tons of AOE damage and threat with Consecration, Avengers Shield, Holy Shield, and Hammer of the Righteous.
You can gain a lot of threat using Consecrate and Holy Shield.
If you are not specced into Consecrate, then Hammer of the Righteous works as well.
While protection paladins generate threat through the use of holy spells, gearing for spell power is not to their advantage since 3.
0, due to their spells now scaling with Attack Power as well as spell power.
Strength is the main stat for threat generation.
Damage Mitigation Paladins do not use high-threat, low damage spells such a warrior would, but instead deals constant large DPS to hold aggro.
Although this sounds great, it is a disadvantage as well.
The disadvantage becomes true when a mob is immune to spell damage.
This makes a paladins tanking job very hard to hold aggro.
This is also true for silence.
Like a warrior, paladins also have access to plate armor and a shield.
Also you are able to block, dodge, and parry.
This makes damage mitigation much easier than if you were to wear cloth...
lol.
Paladins have numerous panic buttons, as well as skills that just make taking less damage that much easier.
Their last skill in the protection tree, Ardent Defender, will reduce incoming damage by 20% for 10 seconds as well as give a chance to revive you if you take a lethal amount of damage.
Their best "emergency button" skill is by far Lay on Hands.
This skill has no Global Cooldown, so you can pop it even if you just activated a different ability, and it restores all of your health.
Lay on Hands is also nice when you are leveling a paladin and run through too many mobs.
This causes the paladin to receive forbearance so he/she will not be able to use a different "emergency button" but it is well worth it when you're in a pickle.
If used on someone other than the paladin then it will not cause forbearance.
Divine protection is another spell that causes forbearance but it will reduce all incoming damage by a whopping 50% for 12 seconds.
This is great when you have a noob pull a million mobs and you don't know how to fix it.
Well, this is your answer.
In case you were wondering, forbearance is a debuff put on you when you use one of these "emergency buttons.
" It reads: "Cannot be affected by Divine Shield, Hand of Protection or Lay on Hands.
"