Free WoW Guide: Priest build: Healing

Improved Renew
Rank: 5/5
Increases the amount healed by your Renew spell by 15%.

Holy Specialization
Rank: 3/5
Increases the critical effect chance of your Holy spells by 3%.

Spiritual Healing
Rank: 5/5
Increases the amount healed by your healing spells by 10%

Subtlety
Rank: 5/5
Reduces the threat generated by your healing spells by 20%.

Improved Flash Heal
Rank: 2/2
Gives you a 70% chance to avoid interruption caused by damage while casting Flash Heal.

Improved Prayer of Healing
Rank: 2/2
Reduces the mana cost of your Prayer of Healing spell by 20%.

Spirit of Redemption
Rank: 1/1
Upon death, summons a Spirit of Redemption that heals nearby friendly targets for 318 to 360 and another 343 over 21 seconds.

Discipline Tree

Unbreakable Will
Rank: 5/5
Increases your chance to resist Stun, Fear and Silence effects by 15%.

Improved Power Word: Shield
Rank: 3/3
Reduces the duration of Power Holy Word: Shield's Weakened Soul effect by 15 seconds.

Improved Power Word: Fortitude
Rank: 2/2
Increases the effect of your Power Word: Fortitude spell by 30%.

Mental Agility
Rank: 5/5
Reduces the mana cost of your instant cast spells by 10%.

Mental Strength
Rank: 5/5
Increases your maximum mana by 10%

Improved Mana Burn
Rank: 2/2
Reduces the casting time of your Mana Burn spell by 0.5 seconds.

Meditation
Rank: 5/5
Allows 15% of your mana to regenerate while casting.

Inner Focus
Rank: 1/1
When activated reduces the Mana cost of your next spell by 100% and increases its critical effect chance by 25% if it is capable of a critical effect.

This is, as the title says, a healing build. It is actually heavier in the Discipline tree than the Holy tree because I feel that extra mana and mana regeneration are more viable talents than some of the higher Holy talents, which improve Greater Heal. Holy Specialization is at 3/5 to access the tier 4 talents of Improved Prayer of Healing and Spirit of Redemption. The numbers listed for Spirit of Redemption are base – they scale with level, and heal for a roughly 1000 burst and 1000 HoT at level 60.

In the Discipline tree, Inner Focus is the end talent to aim for. It is a great spell for any healer to use in a desperate situation. Save it for use on Prayer of Healing or a last ditch Greater Heal on a tank. The talents in the Discipline tree, while not improving healing spells, improve healers in general because they give them a larger mana pool, which is essential, and allow for 15% mana regeneration, which though small, is more useful in end-game raids where boss fights can last for lengthy periods.