There's no solid rotations for healers. The key is always be casting (ABC).

Always have your DoT's up, then spam your stone/broil/malefic. Use your oGCD damagers like Assize on cooldown.

For WHM I like opening with Aero 3>Aero 2> PoM> Stone 4>Stone 4> Assize> Stone 4 spam. Reapply DoT's as needed. Lucid Dreaming at 75% mp, then on cooldown the rest of the fight.

I'm sure you have either a WHM or a Diurnal AST, so let those regens do as much healing as possible. It will become obvious when people need to be topped up right away, and when you can let the regen AOE's do their thing. So dps away while everyone's health is being slowly topped up.