Rotation.

Your main rotation is Crusader Strike > Judgement > Avengers shield > Holy Wrath > Repeat
-Always use Avengers Shield when Grand Crusader pops
-Always start with Avengers Shield if the target is far away
-Do not forget that you can use your Avengers Shield to interrupt spell casting and silence and enemy
Use SoTR when you have 3 holy power and if you reach 70-80% HP use word of glory, always keep in mind of your WoG CD because it could reverse your arena if planned correctly.

Now this is the part that most prot paladins in PvP forget, a magical little spell called 'HOLY SHIELD' This increases the amount you block by 20% for 10 seconds, and with that secondary mastery you've accumulated you should always use this during times of heavy damage eg. when somebody pops their cooldowns. 

Use Hand of Freedom wisely as you still have a 25 second cooldown on it, you can become unstoppable by using it correctly with your pvp trink/racial eg. frost mage uses deep freeze > use your trinket > frost mage uses frost nova and/or wind breath > pop hand of freedom to get close, silence with avengers shield, use hammer of justice before or after the mage blinks away > pop burst and down the mage.

Cleanse is extremely helpful in times of heavy damage as well so use that wisely, keep an eye on your mana whilst using this spell though.

Always help out your partner by throwing a few heals their way or even popping hand of protection on them when they need it, remember that most of the time you can only use hand of protection once in a 2's match so use that only when you know you need to. ALSO REMEMBER THIS DOES NOT PREVENT MAGICAL DAMAGE. 
Helping out your partner is also covered more in the macros section.