Originally Posted by
G l o w y r m
Well I'm assuming you're disc. Make sure you are casting Penance on yourself. Bubble + Penance is an awesome way to recover pretty much half your health VERY quickly while hurting them with reflective shield. Another tip, make sure you're not overhealing yourself. try and heal only really when you need it, with the heal most proper to the speed and type of damage you're taking...without putting yourself in danger of dying of course.
In PVP you have to use pretty much all your spells even if they aren't the most efficient. I'm sure many priests still cast PoM on themselves knowing it will only get used once just because it pretty much negates an attack. Now that's not the most efficient thing but it's a life saver.
Bottom line is, in PVP mana goes fast. All you can do really is just make sure your spec/glyphs are good, and make sure you have decent PVP gear. You'll go OOM from healing yourself so damn much without any resilience. When you do have a decent PVP set it should be somewhere around 17k mana I think, and around 23k hp. You could definitely get better but I would say that's a moderate setup. Also, regen gear is very very important in PVP. A full crit set, while awesome for PVE disc healing, is not going to let you last in a PVP fight, so pick up the spirit PVP gear.