You're right about there being easier ways, and a lot of them involve addons.
I highly recommend picking up Healbot, Vuhdo, or Grid and Clique. I've only ever used Grid + Clique, so that's what I'll talk about.
Grid takes the unit frames (the things that show portrait, health, mana, etc.) and replaces them with your own, which you can customize. with Grid, you can set it up to show whether or not they have Prayer of Mending, Weakened Soul, or just about any other buff or debuff in the game.
Clique allows you to bind certain spells to certain part of your mouse. For example, for me, left-clicking someone's Grid frame will make me cast Flash Heal on them. Right-clicking will make me cast Power Word: Shield on them. Shift-right clicking is Pain Suppression. And so on.
Addons make keeping people shielded, and healing large amounts of people in general, much much easier.
It'll take a bit of tinkering to get some of them to your liking, however. I recommend Googling some of them for guides on how to set them up, especially Grid.
It can take an hour or so to set up to your liking sometimes, but it is worth it.