Resto as a healing spec has some interesting advantages and disadvantages when compared to other healers. In some ways, it stacks very well and in others, it's a trifle limiting. For starters, I have a really difficult time healing a big Karazhan boss fight without Mana Spring totem up. This makes for fun times on any fight where I have to drop some other water totem and, as if often the case, there's no other shaman in the run. Blessing of Wisdom from the pallies can help if we have a pally... but we often don't. I generally have to drop at least one mana potion during a long fight, save Mana Tide for after that, and hope I have another pot available if the fight goes really long. I can't honestly say how this compares to other healers, as I'm usually too busy to notice, but it is a limitation of the class even with decent mp/5 gear. Still, with constant Mana Spring up I'm usually not too bad. The effect of the totem is small, but it helps my natural regen enough to compensate for my mana inefficiency when combined with Wrath of Air totem.
When I feel stressed about how much damage I will be expected to heal I resort to Wrath of Air, which is a boost to caster DPS as well as to my healing. It really depends on two factors - is the DPS in the party melee or caster, and am I expecting the tank to take huge spikes of damage? If the DPS is melee, I'll usually drop Windfury or Grace of Air but if I either expect the tank to take massive bursts of damage or I have more than one caster in the party, I'll drop Wrath for the +101 to their spells and my healing. It's also great for when you're about to drop an Earth Shield on the tank. You can even just drop it for that one cast and then switch to a melee friendly totem.
Last night, while running Black Morass, I never actually used earth shield on the tank except when the wave bosses spawned. Instead, I used it on the feral druid who was killing the adds for us. Honestly, having leveled to 70 as enhancement Earth Shield was the first real 'ooh!' moment for me when I switched. It's a simply great spell and helps to fill the gap in shaman healing from our lack of a heal over time spell. By simply keeping earth shield fresh on the add killer and occasionally throwing a downranked Healing Wave his way when I could, I didn't have to drain my mana too badly to keep him up even though he was far out of range of my mainstay for melee heavy groups, Chain Heal.
I have to say, instances like Black Morass and Steam Vaults have been my training ground in how to learn to become a healer. So it's appropriate that we discuss the three shaman healing spells, Lesser Healing Wave, healing wave and chain heal now.
For starters, I almost never use lesser healing wave when healing in an instance. If I don't have enough mana to cast the rank of healing wave I would want to use, I'll cast a lower ranked healing wave instead. The mana efficiency issue means I'd only cast lesser healing wave if I was convinced the MT was going to die if he didn't get a heal in 1.5 seconds and I didn't have Nature's Swiftness up. I generally depend on healing wave and chain heal to keep everyone up, both due to mana efficiency and the benefit of having enough +healing on my gear that I can use downranked versions and still get decent amounts of healing out of them. My chain heal, which I use at rank one if I can get away with it, tends to heal for about 1200 or so on the first target, so I use it to heal the MT while providing small splash healing for any rogues or ferals up there DPSing. In Black Morass, for instance, we had a warrior and rogue up in melee most of the time with the feral druid switching between the elite and the adds as they popped and the mage providing whatever DPS was most neeeded. So, if I wanted to make sure the rogue (we'll call her Vizz) wasn't going to go down, I might switch to her and fire a couple of chain heals, trusting that the splashover would keep the MT topped off until I could switch to him for a rank 5 healing wave. Vizz stays up, the tank stays up, everyone's happy and I keep enough mana that I can switch to a max rank healing wave if it becomes necessary. Combined with earth shield, sometimes I can actually avoid healing anyone at all for a good ten to fifteen seconds while mana spring and my gear regen some mana for me.
One other trick that having to keep everyone up in a hectic fight has taught me is, throw a rank 1 healing wave on everyone when you can. It only takes 1.5 seconds, it provides Healing Way at a trivial mana cost, and it also has a chance to crit and give them extra armor from Ancestral Healing, if you have that talent. Downranked healing waves that crit may well be all that I could do to keep the druid (we'll call him Vash) alive last night, as he was forced to run in and out of my healing range to deal with the adds.
In general, healing is a 'whatever works' situation. If you prefer to blow all your mana with big heals and it works for you and your groups, then by all means throw the biggest heals you can around. I tend to fanatically downrank my spells whenever possible, casting the lowest rank of a spell that I believe is still getting the benefit of my +healing gear. This used to be even more effective before Blizzard changed how +healing affected lower rank spells, but while it is no longer possible to just downrank and get nearly as much healing for much, much less mana, it's still a useful technique for saving mana and avoiding overhealing. I tend personally to use the lowest effective rank (rank 5 or 6 for healing wave) as a 'spam heal' when necessary, while being ready to hit nature's swiftness and max rank healing wave at a moment's notice. Likewise, my maintenance cast of chain heal is usually rank 1, which still provides a decent amount of group healing for less mana and allows me to keep ahead of the regeneration curve, while always keeping max rank ready to fire into a rogue or other melee DPS who looks to be about to go down.
As a resto shaman, I personally believe I have the tools to main heal any five man in the game and can contribute greatly to healing any raid. We can debate who's the 'best' healer all day, and other classes have strengths I lack... a paladin is a much stronger single target healer, a druid can far outshine me with heal over times, and priests have the single broadest toolkit for healing... but with chain heal I can keep up to three in melee range up indefinitely, and with earth shield I can help reduce the damage a tank takes while giving him or her all the threat generated by that healing, while my healing wave is more than adequate for healing when a big heal is required or only one target is taking damage. Finally, while healing I can drop totems that benefit the group by increasing our mana regen, raising our DPS and even reducing our melee damage taken. And it's always fun to drop a Fire Elemental and pop Bloodlust then go back to healing.
What I know about healing, I've learned through instancing and raiding. You can read up on healing builds (in fact, I recommend that you do) but in the end, the best teacher is going to be trying desperately to come up with a way to keep the mage alive even though he's behind you and the rest of the party is in front of you, or screaming obscenities at your screen because the shadow priest keeps taking massive damage because his mind control breaks early. Ah, nature's swiftness, without you I'd have popped a blood vessel by now.
Now, come forth and share your own tales of healing resto. Next week, we'll be talking resto gear for starting out in the 70 mans as well as some nice pieces for when you're leveling up, and then we move on to discuss elemental, if all goes according to plan.