Healing and moving This is one of the most basic skills, and I still notice a number of healers out there who seem to be playing with lead feet. Yes, there are spells where you need to stand still and heal. But there are going to be times where your healing targets are kiting something or have to keep moving. Shannox is a good example of this. Either have a prearranged idea of where your tanks and other targets are going, or you'd better learn how to close the distance gap in order to heal them.
Mana management Knowing when to conserve mana is another aspect that comes with time and practice. Some encounters have burn phases, except what's being burned isn't the boss -- it's the raid! Do you have enough mana left in the tank to keep them alive long enough to do the job? If you made the right choices earlier on about which spells to use and which targets to heal, then you'll be in a solid shape for the future. Don't triple-shift and heal the same person. Don't use a fast heal when a slow one would work. Don't burn a bomb heal when a HOT spell can do the job.
Priority healing Do you know about triage healing? This refers to the ability to target the players around you who are under the biggest threat of dying. For example, you might have a player at 10% health after taking a large AOE hit, followed by a tank who's taking a continual beating from the boss that he's tanking with his health floating at 45%. Assuming there aren't any other abilities coming out that can mess up the rest of the raid team, your ideal course of action is to sustain your tank. This type of thinking takes practice and constant healing to do. It doesn't matter if it is being done in raids, heroics or battlegrounds. At the most basic form, healing is the act of keeping players alive in the face of threats.
Cooldown spells Now, this can go one of two possible ways. Either your raid leader coordinates healing cooldowns as needed (such as on Majordomo Staghelm), or you're given full discretion on when and where to use them. Cooldown usage requires twitchy reflexes. You're not always going to know in advance when to use any kind of tank survival spells. It is a split-second decision, where the right call means the tank lives and the encounter keeps going or the wrong call is made and the cooldown is burned or unused, which could result in an eventual wipe. Overall raiding cooldowns can be a headache since it can fall to the raid leader to decide when it needs to be used. On the other hand, maybe it ends up being a dynamic encounter and you're given free control over when to use your spells. Check with your leaders if you're unsure. It pays to have full knowledge of what you're up again. For that you'll want to refer to the next point being made after this.
Stuff that kills healers and tanks Are you aware of the different threats in an encounter? Do you know what abilities can kill tanks or spell doom for other players? Having an in-depth knowledge of what can destroy the raid and what can't allows you to plan your positioning and spell use accordingly. Maybe there's a phase when you don't have to stress heal as much, and can afford to sit back and regenerate a little bit. By being prepared and knowing what to expect, you can deal with the threats easily.
Willingness to bail players out Sometimes you just need to keep your mouth shut and your ego in check. Yes, I get that there are always going to be players who don't learn and continually expose themselves to dangers that they shouldn't otherwise be doing. Swallow your pride and do what you can to heal them (and feel free to yell at them so that they wake up). Let your leaders take care of them after the attempt is over. If someone's consistently playing poorly, you need to alert your leaders or tell the players yourself (depending on how your raiding group handles that). When you're in the battlefield healing, there is no such thing as fair. Sometimes you just need to heal idiots so you can get through to the end of the tunnel. If you can't keep them alive, move on to the next person. At the very least, you should try your best to save them. Healing is going to be full of challenges. The biggest challenge comes from your own teammates.
Burst healing I would define this as the ability to dump a high amount of healing per second on to one or multiple targets. You need to know what set or sequence of healing spells will cause the most healing in a short amount of time. If the tank had 5 seconds to live, what spells in what order could be used to shoot him back up again? Baleroc is a great example of this. If a tank just ate a Decimation Blade, what would you do to spike his health back up again? If your party of five players is being hammered, what can you do to counteract the damage being done until the boss stops the ability?
These are what I would refer to as transferable skills. They're applicable to any healing class (or heck, to any game where healing is a role). Are there any other basics that you would add to this list? Skills that you've found invaluable, perhaps, or things you find yourself teaching to other healers in your guild who are new?
Need advice on working with the healers in your guild? Raid Rx has you covered. Send your questions about raid healing to firstname.lastname@example.org. For less healer-centric raiding advice, visit Ready Check for advanced tactics and advice for the endgame raider.