When a pull turns
Use
Hammer of Justice to interrupt the mob's heal cast. Avoid a caster pull while it is cooling down.Use
Divine Shield to open a 
Holy Light window, heal, and leave the pull while it is active.
Lay on Hands is for the pull that needs a full health reset after Divine Shield is down.
Blessing of Freedom clears roots and slows, so use it when the retreat lane closes.
Dungeon calls
Blessing of Wisdom goes on the healer and Might on melee. Refresh both before the pull.
In Retribution gear, decline the off-tank role before the pull.
Stop for the healer's drink because Blessing of Wisdom does not replace it.
Leave now
Leave when mana drops below 20% and the pull remains open.
Leave when Divine Shield is used and Lay on Hands is cooling down.
Leave when two casters land while Hammer of Justice is cooling down.
Leave when a patrol arrives and the retreat lane is hostile.