One additional element that I think cannot be overlooked that helps you with situation awareness is your HUD. This goes for any class really, but more so for healers because unlike DPS or maybe even the tank, your focus is on everyone, including yourself.

--Optimize hotbar positioning to reduce move movement across the entire screen
--Optimize HUD layout so that important items are at eye level
--Keybind important pet functions (e.g. Embrace)
--Pay attention to line of sight and distance from teammates

Lastly, as a SCH -- I've found that I've messed up MOST when I've gotten too distracted applying DOTS too much. Priorities 1, 2 and 3 are healing, healing and more healing. If you start applying your std DOT rotation on a large pull ( 4 - 5 mobs) and the tank a huge burst of damage, you may have lost critical seconds to get him back in a safe range.
That's my 2 cents..