I've tried about every possible shammy build. I switched between elemental and enhancement for leveling (enhancement is better for that, I think), and now that I'm finally 70, I respecced resto. Tried resto/ele at first, but it didn't really work for me - to get the true shine of shamanic healing, you'll need to throw most of your talents in restoration tree.
http://eu.wowarmory.com/character-talen ... &n=EuryaleThis is how I solved this. And why? Here, in taking order, not in tier order:
* 5 improved healing wave - rather obvious
* 5 tidal focus - shaman always lacks mana. Probably won't be so awfull since 2.3, but untill then, it's a must have.
* 5 healing focus - in a perfect party you shouldn't get hit, but well, perfect never happens. Must have.
* 5 restorative totems - not really that great, but since it leads to mana tide totem, you have to get it.
* 1 nature swiftness - if anything goes wrong (sudden boss crit, adds pull, etc), this is gonna save your tank. <3
* 3 healing way - there's a nice little trick involving this one - get you healing wave rank one linked somewhere, and before a boss fight throw it on your tank, so it stacks three times. HW1 takes so little mana, that it's usually covered by your mp5, so it's a cool free buff for your tank.
* 1 totemic mastery - we have one free point left before we get to higher tier, and more totems range is nice to have, since you'll be trying to get away from melee range, so let's get this one.
* 5 purification - also obvious.
* 1 mana tide - it'll save your party a lot. As I said, shamans always get out of mana. It's built-in the class. So in longer fights, especially for bosses, you'll have to throw this totem.
now, four points left till we go higher...
* 3 healing grace - for singular mob, you won't have to worry about threat at all. But when the tank manages a group, especially one with casters, this'll help you a bit, since shamans have no built-in threat reduction. (You should probably get Subtlety on cloak too, I sure will once I get my epic mount.)
* 1 tidal mastery - this one is arguable, but I like it. It's a bit of a luck thing, but a nicely timed critical heal can help. Will throw 4 additional points here once we have it.

* 2 improved chain heal - quite self-explanatory. Works especially well in battlegrounds, but should be good for raids, too - don't know, I don't raid yet.
* 3 nature's blessing - that's +100 spell damage and healing for me atm, but most importantly, it leads us to
* 1 Earth Shield - the ultimate healing spell of doom. No, really. Costs only 600 mana, you'll throw it on your tank and then you can lie down and watch it work. Yeah, kidding, but only a bit - you shouldn't have to heal your tank too much through most of trash group in instances, and it helps a lot when fighting bosses. What's even better, it moves the threat to your tank instead of you. <3
Now we're on the top of resto tree, let's fill up those gaps and use the extra points.
* 3 - ancestral healing - another nice little free buff for your tank; works well with the rank one healing wave trick.
* up to 5 - tidal mastery
* 5 points into the enhancement tree - ancestral knowledge. More mana!
We're left with 8 points you can spend on whatever you like. I threw
* 2 Guarding Totems - in enhancement tree, mostly for reduced cooldown on Grounding Totem
* 2 Improved Reincarnation - mostly because there was nothing else to take, but it works surprisingly well, which actually means that I die more than I should. :< Helped me a lot yesterday in heroic Slave Pens - it was my first heroic run ever - and my build worked well! Unfortunatelly we didn't have much Crowd Control, and I died so often, I was down to 8% in gear durability at the end. But we did it!

* 4 Totemic Focus - if you throw totems before the combat, it doesn't matter how much they cost, because you'll hace a few seconds to drink anyway. But often you'll have to retotemize in the middle of a group/boss fight, when every mana point matter. I should probably make that 1 improved reincarnation/5 totemic focus, but I won't be bothered now, it works anyway.
What I didn't take and why:
Nature's Guidance - it's a support talent for dps spec. Skip for resto.
Focused Mind - PvP talent. I don't do PvP except for occasional AV run (I love those, mostly because there's not much PvP involved

), so - skip.
Nature's Guardian - yeah, a talent for healer based on how badly hit you are. </3 Skip, if you're getting below 30%, you'll probably wipe anyway.
Using it is quite simple - in instances have the Earth Shield up on your tank and remember to save your mana in longer encounters. Downranking the Healing Wave is the key - it's quite a long cast spell, though, so in emergency you'll want to use Lesser Healing Wave (fast healing for lower amount) or Nature's Swiftness + Healing Wave. If you have a group of melee dps, it's a good idea to throw a chain heal every once in a while, if there are ranged dps - well, they shouldn't get hit.

Also, healing done by the Earth Shield is based on your +heal in the moment you cast it, not when it procs, so before a boss fight, it's a good idea to throw your wrath of air totem, use your trinkets, buff the Earth Shield on your tank and regenerate mana.
There's also a great strategy for really hard encounters - canceling your heals. You'll need to watch the action carefully for this one, though; high fps and low latency is handy too. You'll have to watch a person who'll potentially get hit (a mage who's sheep broke, a trapping hunter) and start casting a heal; then, if they won't get damage - cancel the spell by hitting escape/moving/jumping (I find jumping too slow and escape hard to hit, so I usually move back/forward one step) and repeat untill the danger is over. Very stressfull, requires much attention, but also very mana efficient and can make a difference between a succesfull run and a wipe.
Is there anyone interested in playing Shaman out there, anyway?

If anyone's interested, I can cover gear and enchants, too...