http://www.wow-europe.com/en/info/basic ... 0000000000This is the outline of the tri-spec grinding build I am using on the brand spanking new rp/pvp realm. Yes, the points in PW:Shield are arguably worthless before 60. But the only real option is putting them in Silent Resolve, and that is arguably just as worthless pre 60. Do what you will with those 2 points, it's not going to matter either way.
Breaking it down a bit:
Get Wand Specialization first. You're going to be shooting alot with that wand. This is a good dps boost early.
Second get Spirit Tap
Then fill out disc tree to Divine Spirit. Then healing tree to Holy Nova.
You are done with this at level 46. You got all the essentials of solo grinding, and make an excellent sidekick for an AE mage.
My fights go like this against a +1/2 level mob:
1. Put on PW:Shield
2. Pull with Holy Fire
3. Stack on SW:P
4. Smite (yes, smite, not Mind Blast)*
5. Wand to death
*) I usually skip the smite if the Holy Fire critted.
With Divine Spirit, Spirit Tap, gear with lots of +spirit and using the wand to finish em off you literally never have to drink. Yes, a single enemy takes a couple of seconds longer to kill than using Mind Flay in Shadow Form, but you don't have to drink for 24 seconds after every third kill either.
If you go for the old truth that grinding -2 is optimal then just remove the smite from the routine. (I guess it _is_ optimal. It's just insanely boring!) If you grind on -2 you can ditch PW:shield and heal as necessary. Which is far more mana efficient, not that it's necessary.
Why Smite and not Mind Blast? Mana efficiency and crit chance combined makes the answer obvious really. (You're not losing casting time, as you have shield up.)
After this it's up to you if you want to edge toward a 31/20 or a 21/30 build. When you are done faction grinding at 60 and almost exclusively run instances you'll respec out of of the Spirit Tap into a pure 31/20 or 21/30 build. (I am firmly of the belief that skipping Lightwell for either Power Infusion or Divine Spirit is your best bet, depending on how deep you want to go in the disc tree.)
This is all from a PvE perspective. You're going to be a pvp gimp much of the time, especially in the 40-49 stretch.
SvD.