Post by Aldones
Practice... That's all you need.
That's the number one piece of advice I can give you.
As far as which spec, discipline or holy, you need a crash course on both of those to figure out which one you think you like best and how to play it. Then try it out. I haven't posted anything on here in a while, so I don't know how up to date the stickies are, but I'd still recommend looking at them.
Discipline: A quick heal, single target, damage mitigating class. We are best know for preventing damage through our many shields. However, this has a big side effect; shields don't show up on recount. So, if you care about healing meters, you will probably regret going disc. Still, it's hard to beat
Penance (3 ticks, one of them being instant), and you will make many new caster dps friends with
PI.
Holy: A slower heal, AoE healing class. With the 3.2 changes, holy became a little bit trickier to play, but is still fairly simple. The trick is to stack up
Serendipity and then either use it on a
GH or a
PoH. Holy also comes with the added benefit of an additional AoE spell,
CoH.
With healer unit frames, go with either healbot or grid+clique (2 separate addons working together). I found healbot easier to learn my initial healing since it is slightly easier to setup and it gives more room to desplay icons to help you know what is going on, but once again we run into the side effect, more room makes it bulky and you will have trouble doing anything in a 25 man raid...if you set it to 40 man and you can say byebye to about half your screen.
With that in mind, many healers go with grid+clique which can show even more, but in a much more compact area. For example, in that little grid box I track, magic and disease debuffs, weakened soul debuff, aggro, who and what stack of Grace (I'm disc), who and how many bounces left on PoM, my renew and it's timer, and everyone's hp, mana, rage, energy, and/or runic power. It's actually quite a bit simpler than you might think.