So, I thought I'd talk about that thing all Balance druids should know how to do: heal. I've said it before and I'll say it again: a Balance specced druid who refuses to pop out of Moonkin and heal if it is needed is a liability, and should have just rolled a mage.
I'm going to use our guild's Karazhan experience as an example.
First off, we run with 2 healers. I know a lot of guilds do it with 3. Now, we're not the best guild in the world, but we've made very quick progress for a casual raiding guild. I think a lot of it is because we're using that slightly atypical 2-healer configuration.
A lot of people say that off-heals aren't desired in raids, but at least in a 10 man group, it means there's one more person pumping out great DPS if there's not a dedicated healer there. Do I top the damage meters? Usually not, I'm usually about midway down the DPS. If your aim as a Balance druid is to "win" the damage meter contest, again, you rolled the wrong class.
The first thing you need to do is practice situational awareness. Get your eyes unglued from the boss and start looking at stuff around you. How are your compatriots doing? Is one of the main healers getting low on mana? Did the melee DPS just get unlucky and take an AOE crit in the teeth?
To help with this, I recommend getting some sort of healing mod. I personally use CEasyHealer, mostly because I'm used to it and I like the click functionality. Basically, it's just a bunch of squares, one for each raid member. Each square displays the person's health as a percentage, and you just have to click (or ctrl- or shift- click) to cast different heals on them. This makes it a lot easier for me to toss a heal or two without wasting time switching targets. There are a ton of similar mods out there, find one you like. Communicate with your healers. Make sure they're aware that you are going to be spot healing if needed. Let them direct you if they have any specific needs.
You're probably already accustomed to using your innervate on healers, rather than yourself. You can take this one step further and make your priests/shamans/resto druids really love you (I leave out holy pallies, because innervate is nearly useless for them). As long as you're confident you can main heal for 10-15 seconds, let the healer get into the five second rule, use your innervate on them, and start healing while they take a 10 second nap. This means that rather than the 100% mana regen they'd normally get because they're casting, they'll end up with 400% mana regen. That's 4 times as much mana from the innervate. Now obviously, don't try this if the tank is holding on by a thread and will go splat when your inferior heals can't keep up.
NOTE: It's been brought to my attention that my assertions in the paragraph above may be incorrect. I'll have to test it out myself, I haven't done so since somewhere around level 50.
Your best bet for off healing is using instant-cast heal over time spells, maybe with the occasional regrowth tossed in. You're generally going to want to avoid healing touch, as it will just chew through your mana. Plus, it's a big, slow heal. You want to aim more for topping off, or for keeping someone alive until a main healer's big, slow heal can put them all the way back up.
If you're needed to help ease spike damage on one or two targets with HoTs, use and abuse lifebloom. It effectively allows you to triple your +healing. Here's a quick rundown.
In WoW 2.1, each application of Lifebloom adds the full amount per tick, essentially doubling or tripling the amount healed each second. Now this is strong, no doubt, but there are several factors associated with Lifebloom that are what really make it shine.So, a typical spell rotation when you're dedicated to topping off the tank might be Lifebloomx3, Starfire, Starfire, Lifebloom, etc. If you're finding yourself losing the 3 stack, make it Lifebloomx3, Starfire, Wrath, Lifebloom.
1.) Once there are three stacks on a target it will stay at three stacks as long as it is refreshed before the Lifebloom expires and explodes, e.g. within seven seconds. By maintaining a Lifebloom triple stack the target will receive up to six ticks of triple healing for the cost of one spell each time it is reapplied.
2.) The amount each stack heals for is set by the +Healing at the time the stack was first applied. As long as it is not allowed to explode, the Druid could even remove all their Healing gear and still keep the Lifebloom ticking for the same amount.
3.) In a stacked Lifebloom, since the amount healed for is triple the normal amount for the spell, the effect of +Healing added to the spell is in effect also tripled. Because of this the +Healing stat gains more impact than it normally does in other situations or for other healers.
The key to success with Lifebloom is that not only can it do a large amount of healing when stacked, but maintaining this only takes 1.5 seconds of cooldown out of every six to seven second casting sequence. This leaves the Druid free to use approximately five seconds of casting or cooldown time to cast other spells in-between refreshing the Lifebloom, and also allows them freedom of movement due to the nature of instant cast spells.
So, apart from the math tips, it's all pretty much common sense. Keep your eyes open, follow the direction of your main healers, and keep people alive. Remember, if someone dies because you chose not to interrupt one of your starfire/wrath casts, you just cost the team all the future DPS of that team member for what, maybe 4k-5k of damage if you crit hugely? Balance druid doesn't mean "LoLz I nukzorz you," it means exactly what it says, Balance. You're an asset not so much because you are a weapon, but because you are a weapon AND a team player.