cure/cure 2 = single target?
Medica/medica2/cure3 = raid heal? medica2 once then medica medica if the aoe dmg is huge
presence of mind + divine seal = emergency periods of heal
stoneskin = mitigation for huge amount of incoming dmg when ur tank is already topped up

A good way to do dungeon is to go youtube first and watch a vid of that dungeon once or twice to familiarise or get an idea of what is going on. Once u are familiar with the mechanics, it shd be v easy to heal