Several people have been asking me to make a guide to playing a protection paladin, so here we go. Ultimately, I hope that people will post similar guides for other specs/classes so newer players at each class can benefit from their experience, but we'll just start here for now

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First thing to discuss is the talent spec. I am currently using a
5/60/6 build. This build has everything useful in the prot tree, basically, and all the essential talents from outside the tree. If you want you can trade BoK, Divine Guardian and maybe Judgments of the Just in for things in the ret tree (such as Benediction, Conviction, etc). I do not recommend adding two points to improved Judgments, as having it on an 8 second cooldown will not speed up your rotation any, and so is a waste of a talent point. However, having the one point is essential. Also, I would not recommend picking up Reckoning, as it doesn't proc terribly often, and the effect is not strong when most of your threat comes from abilites.
When the next patch comes out, this will all change, and I will post an updated talent tree.
The rotation that you should follow is known, colloquially at least, as a 9/6/9/6/9 rotation, as all of our main tanking skills either have a cooldown of 6 seconds, or 9 (8) seconds. The general idea is to always have Seal of Vengeance up, pull with Avenger's Shield, then follow the rotation as follows:
Holy Shield
Hammer of the Righteous
Judgment (of Wisdom)
Shield of Righteousness
Consecrate
Hammer
Holy Shield
Shield of Righteousness
Judgment
Hammer
etc
Ultimately you have two rotations going at once, one between Hammer and Shield of righteousness with their 6 second cooldowns, and one of Consecrate, Holy Shield and Judgement with their 8/9 sec cooldowns. If you have to drop something due to low mana/needing to cast Divine Plea/Hammer of Wrath/Hammer of Justice/etc, Consecrate is usually the best spell to drop, especially once you get the
badge libram.
As for Glyphs, the Glyphs of Judgement and Seal of Vengeance are absolutely required at this point. Your third glyph is personal choice. I use Glyph of Spiritual Attunement, but you can use the Glyphs of Righteous Defense or Exorcism or Avenger's Shield as well. Minor glyphs are up to personal choice as well. Once 3.1 comes out, Glyph of Divine Plea will be by far the best choice for your third slot.
Next, macros. There are only a handful of macros that are really necessary at this point, as they have changed the way a lot of spells work so the macro is not essential. The Righteous Defense macro used to be essential, and in my mind still is. It can be used without a macro, but I prefer the added flexibility the macro provides. It is:
#showtooltip Righteous Defense
/cast [help,nodead][target=targettarget,help,nodead]Righteous Defense
I also use a cancelaura macro with Divine Shield so I can quickly get terrible debuffs off of myself. It has a five minute cooldown, but it breaks nearly everything you want it to (fear, most webs, uncleansable poisons, etc) It is:
/cancelaura Divine Shield
/cast Divine Shield
I have the cancelaura part first so I can use it as a normal divine shield if necessary. I also have three self cast macros that are really easy. I have them all on easily reachable keys so I can cleanse myself, Lay on Hands myself or Hand of Freedom myself as necessary. The general way of making these is:
#showtooltip
/cast [target=player] Lay on Hands
You can also do macros similar to your Righteous Defense macro to quickly Hand of Protection or Hand of Salvation someone who has pulled aggro, but these are more dangerous, because you might end up casting them on yourself, as Hand of Salvation/Protection can be cast on yourself while Righteous Defense cannot.
#showtooltip Hand of Salvation
/cast [help,nodead][target=targettarget,help,nodead]Hand of Salvation
In terms of gear you are looking for the same gear as most other tanks. You will generally not have quite as high HP as other tanks, but you make up for it with much higher mitigation of damage through Holy Shield, high block values, and Ardent Defender. Things with Block rating/block value are slightly more valuable to you than to other tanks, but Dodge and Parry are still excellent as well. Ultimately you want a good balance between the three. It is possible with good gear to be so that you cannot be hit normally when you have Holy Shield up, but that requires excellent gear.
That is all I can think of at the moment. If anyone has any questions, please let me know

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