Make sure your PvP skills are available. As a paladin you have the best stun in PvP, but like in PvE, it has diminishing returns. More generally, try to have good situational awareness and not run into packs of enemies (even if your ranged are sniping at each other).

As a healer, I <3 PLDs that use cover on me. Healers have it pretty rough in PvP so if you want to be especially nice, try to peel off attackers focusing on them.