For the majority of the fight, you're basically a heal turret. You have many defensive spells such as Fluid Aura, Repose, Blizz2, Stone2, Virus, aether burst, focals.
-Fluid Aura & Repose can go hand-in-hand, it can be used offensively on the opposing healer or defensively to get the pesky dps/tank off you. A great cc combo would be to Fluid Aura and Repose your target, it's really disruptive on the opposing healer if used strategically, so knowing when a good time to use it can be almost game changing. Don't go reposing targets if your dps are 50% hp!
Strategies?: throw asylum/prism down near some sort of wall, regen self, make use of the wall, bind your targets (blizz2) on one side, run to the other side and heal yourself. Or just straight up run, trying to LoS as much as possible. Use surecast & equanimity!
The rest comes with experience, and learning from it. I probably missed a lot but that's as much as I can think of at the moment!
Good luck, I hope I helped in some way