Build This is the
standard Holy Tree build. Imp LoH vs Unyielding faith is debatable, but Mal'ganis is PvP and honestly LoH will only be used once in a blue moon and the bonuses are not enough to make it worth having. 20 points can go down Prot for PvP purposes, Guardians favour, Imp Conc Aura etc. Or you can spec 5 points into Imp BoM, and go into Prot to get BoK for raid buffage purposes. Where you spend your other 20 points is personal preference, don't go too heavy into the Holy tree with extra points and don't try to be a ret hybrid (/ewww).
Gear Terms of gear at your point you will take plate, mail, leather or cloth. Whatever has the best blend of stats for you. Try to build a strictly +healing set, and then have a leveling set on the side.
Stats Spirit is useless for pallies.
Int is the base stat, increases mana pool, +healing, and spellcrit.
Mp5 vs Spellcrit. Early on you will use FoL a lot so Mp5 is your friend since they compliment each other. Don't neglect spell crit though. As you progress it becomes necessary to stack more and more spellcrit as you bring Holy Light into your rotation.
+heal by the time you are looking at Karazhan you will need 1000 absolute bare fricking minimum, 1100-1200 recommended.
Add ons
Healbot to start, I prefer Grid + Clique for healing, but a lot of new pallies prefer Healbot since it is easier to set up. Basically both give you full views of groups and healing situation and allow you to assign mouse clicks to healing casts, so I can left click on a guy and it casts FoL, as a healer .5 seconds can be the difference between the heal getting off and the tank dying, this is where you get that .5 seconds.
Omen - Watch your threat, make sure your guild mates use it as well. Pretty much mandatory for PvE now.
Deadly Boss Mods/ Big Wigs if you go into Karazhan
Pallypower is an absolute must if you are a pally. I don't care what spec, get it, get it now. Makes buffing about 100 times easier, especially with multiple pallies in the group.