First of all talents.
Deap healing without spirit buff
With spirit buff
FAQ:
Q: Is Circle of Healing (CoH) worth it?
A: Depends on your level of content. If you're in T4 content, short
answer is no. If you're in SSC/TK, it is situationally powerful. If
you're in BT/HS, yes. Absolutely. Additionally, if you are going deep
Holy (for 5/5 Emp Healing), you might as well take CoH, as the only
other thing you can get is regular Divine Spirit, which someone else in
your raid should already have.
Q: Is Lightwell worth a talent point?
A: Most people who use it think that it is, especially post 2.2.2. It
heals for around 4500 per click now, providing a partial top-up heal
for fights like Naj'entus where the raid takes predictable raid-wide
damage. If you chose to not take this talent point, there's not a lot
you can take that is better: usually Holy Reach or Holy Specialization
is chosen.
Q: What level of gear should I have ?
A: To run Karazhan: 1400 +heal, 180 Mp5 *or* 400 spirit. Easily obtained through crafted pieces.
At the end of Karazhan: 1600 +heal, 200 Mp5 *or* 500 spirit.
At the end of T4 content: 1700 +heal, 200 Mp5 *or* 500 spirit (don't gain much from Gruul/Mag)
At the end of T5 content: 2000 +heal, 230 Mp5 *or* 600 spirit.
Gemming
Q: What gems do priest use?
A: [Royal Nightseye].
[Dazzling Talasite] if you want a set bonus and need a yellow gem.
(or [Luminous Noble Topaz])
[Teardrop Living Ruby] for red sockets if you like stacking +heal.
Metagems
[Insightful Earthstorm Diamond]:
the most useful, and easiest to equip, metagem. The proc goes off quite
often, and typically restores 4000+ mana over a 10 minute fight. Very
useful, and the intellect also helps.
[Bracing Earthstorm Diamond]:
useful metagem, but extremely difficult to equip given priest gem
setups. Having Yellow>Red>Blue basically screws over our use of [Royal Nightseye],
and given that Yellow gems are the most worthless, is really not worth
equipping. Leave this one to a paladin who stacks crit gems.
[Mystical Skyfire Diamond]:
easy to equip, but only really useful if you are spamming on a single
target. The haste proc is powerful, and can be a significant part of
your play style if you mess around with it and learn how to use it.