This is not about healing in SWTOR, this is a very very broad overview of healing in MMO’s in general.
Healing is all about “just enough.” With DPS, you want to do as much as possible, period. With tanking, if you have extra threat, so what? With healing, you are constantly balancing health versus your force/energy/ammo bar.
HPM versus HPS
Oh noes, scary letters! Breathe. Let me explain.
HPM = Heal Per Mana. In our case, it’s force/energy/ammo and totally not mana, because that’s so “WoW”, right? This means what is the heal going to COST you. After all, a healer who is out of mana is a useless healer and people start croaking.
HPS = Heal Per Second. This means how much health you’re delivering in a given amount of time. How fast are you filling up those health bars.
Each healer of every class has hard-hitting expensive heals (High HPS, Low HPM), and slow-ass cheap heals (Low HPS, High HPM). Your job as a healer is to judge incoming damage and balance between HPS and HPM.
That’s it. Really. If the tank is taking slow damage, you can use cheapie heals. If the tank is dropping fast, you use the big fat mana-hoggy heal-bombs and hope that you will have time later to use cheapie heals and build up your resource pool again.
It’s Probably Not Your Fault
Sure, if you ONLY use your big fat hoggy heals and run yourself out of mana early and the whole group dies, maybe you’re doing it wrong. However, could you have used anything smaller at any point? Did you need to spam those huge heals to keep people from croaking? If so, it’s not your problem. Someone ELSE was effing up. Maybe the encounter was too hard. Maybe morons were standing in the fire. Maybe the tank overpulled. Maybe the tank forgot he had cooldowns that he could have used to mitigate the damage. Maybe there was crowd control fail.
Not every death is your fault. In fact, most of them are NOT. Remember that. And if someone dares to blame you, come down with the fury of Alvis and smite his sorry ass.
Practice Healing
I know, this is DUH, but bear with me. It is FAR easier to level as DPS and switch to healing later, and that’s fine. But before you throw yourself hyperventilating into a flashpoint, why don’t you do some heroic quests with your buddies? Maybe it’s “too easy” but it’s the laboratory where you can learn.
How much of the health bar does the heal fill? How much of my mana bar does it consume? Often you’ll be eyeballing the health bars and soon you’ll know exactly the right heal for 1/4 a bar.
It’s a good way to get comfortable with the slow-ass cheapie heals. Often when you get into your first flashpoint, you kinda panic and go “zomg everyone’s gonna DIEEEE” and start throwing out the heal-bombs and next thing you’re out of mana. Practicing can give you the confidence to say “this will take care of the damage, nobody will die in the next 3 seconds, I CAN afford to be cheap.”
And finally… where your buttons are. You do not want to be FUMBLING later. Half of this is muscle memory. I am a total dork for about a day after I move any keybinds.
Attitude
The last thing you should take away is that you are super-important. You are more important than anyone else in your group. The tank may feel important, but he’s a loser. You are the backbone of the group. They will die without you.
It is totally ok to let someone die on purpose. You won’t get dark side points. Don’t do it just to be mean. Ok, you can do it to be mean, but not too often. If they can’t get their asses out of the fire, they need to learn the hard way. There are times where you are skilled enough to pull out the miracles to save someone who is about to die. Whether you choose to go to those extreme lengths is up to you.
If you are out of mana (or whatever) you can (and should) stop the entire group and tell them STOP AND I HAVE TO REGENERATE. If they wander off anyway, they are just asking to die.
DPS are a dime a dozen. You are a superstar. They need you. Never forget that.