Skill rotation and mana usage
We think you can go almost indefinetely on mana by using Divine Storm, Crusader Strike and a Seal / Judgement. If you want to add things to that, Consecration, Hammer or a heal perhaps, your mana will start to dip, but Divine Plea should make up for that. In PvP, you can make the choice to blow all of your mana knowing that you have time before the next fight to build your reserves back up. Or if you want to go from target to target with no downtime, don't blow all of your mana.