For FL, make sure you are actively observing the situation. This sounds obvious, but new healers have a problem of focusing too much on the vitals to the side of their screen; helpful, but doesn't tell the story. For example, tanks and melee who are diving at 50% HP deserve your attention more than a ranged DPS at 25% HP behind you. The process of triage and priority is not new to healing in FFXIV, though the economics of warfare and the outcome of where your attention lies will change. For instance, supporting someone diving into the backline of the enemy team can mean winning an engagement at a critical point of the map, leading to a rout or allowing your team to rotate elsewhere. Meanwhile letting that target die to prioritize someone who needed that healing less critically may just lead to a prolonged encounter, so it can have pretty vivid ramifications.

Needless to say, Temperance, Dia, Glare, and Afflatus Misery, and to an extent Assize, can all be combined into a rather large burst sequence which can be modified based on what you have available or what you may need momentarily. Taking down a third of someone's healthbar isn't bad a for a healer, though Temperance has a pretty substantial defensive benefit so use discretion.