Protection Paladin
Rotation
Opener: Blessing of Sanctuary on yourself, Righteous Fury on, Seal of the Crusader then Judgement, swap to Seal of Righteousness.
Priority: Holy Shield on cooldown, Consecration on packs, Judgement of Righteousness on cooldown, Seal of Righteousness twists in between. Taunt and Hand of Reckoning for pickups.
Cooldowns: Divine Protection cannot be used while tanking (you lose threat); use Lay on Hands as your emergency button.
Forever notes: Forever reworked Protection around Holy Shield and Avenger's Shield-style tools; the talents page has the current tree. Mana is the limit: Blessing of Wisdom and Spiritual Attunement keep you casting.
Stats
Stamina, Defense and avoidance first, then Block Value (Holy Shield and Reckoning), then Spell Power for Holy Shield and Consecration threat, then Intellect for the mana to keep casting.
Threat is spell-based, so a caster mace plus shield can out-tank a 'tank' weapon.
Numbers for every spec and a gear comparer: stat weights.
Where it ranks
See the tier lists for PvE and PvP placement, and Classic vs Forever changes for what Blizzard altered in this class.
Wowhead and Icy Veins keep spec guides of their own: Icy Veins Protection Paladin, Wowhead class guides. Our rotation notes are editorial, written for the Nov 2 tuning.