Discipline is a good spec for leveling for a balanced mixture of Healing and Damage. This is the best overall spec for leveling as you won’t have any problem healing in Dungeons and you can easily dump all your mana in for killing NPC while solo questing.

Prime Glyphs: Penance , Shadow Word: Pain , Power Word: Shield

Major Glyphs: Smite , Holy Nova , Spirit Tap

Shadow provides the highest DPS out of the three spec available, but it doesn’t provide any healing talents at all. You can still heal in dungeons with this spec but you will have to be very conservative with your mana.

Prime Glyphs: Dispersion , Shadow Word: Pain , Mind Flay

Major Glyphs: Spirit Tap , Inner Fire , Psychic Horror

Holy is the best healing spec and it is recommended for end game raiding and dungeons only. There’s not much talent that will increase your damage and would make a terrible solo leveling

Prime Glyphs: Guardian Spirit , Renew , Flash Heal

Major Glyphs: Holy Nova , Spirit of Redemption , Fade