Playstyle & Rotation
Healing doesn’t have a rotation and it is important to be flexible in whatever endgame content you find yourself in but here are some guidelines to follow:
Use Light of the Martyr sparingly. It should be used whilst you’re on the move if you have no other instant cast spells available to you in that moment of movement.
If you’re playing with Rule of Law, you want to use it mainly when casting Light of Dawn to minimise its potential wastage (if your raid isn’t stacked) or when the raid is spread over a large distance. For example, the Sun King’s Salvation raid encounter might have some range issues in the fight for healers unless you’re standing in the middle of the encounter area.
Beacon of Light overhealing is a variant to keep an eye on. Your beacon is most valuable on a tank that will take the most consistent damage, like a Brewmaster Monk for example. Self-sustaining tanks like Blood death knights and Vengeance Demon Hunters could cause your Beacon of Light to overheal more than usual.
In periods between raid damage on boss encounters, be sure to squeeze in damage with Consecration, Shield of the Righteous and the occasional Holy Shock just to sustain the Glimmer of Light debuff (if talented). This is a good habit to get into as being afk between raid damage events isn’t ideal for your group leader.