Big thing is to avoid overhealing, you want to use mostly Cure, and keep Cure II to Freecure procs or emergancy. Make use of regen, for a tank taking damage, or for dps that has taken damage but shouldn't again for a while.

Use shroud of saints earlier in a fight and you'll be able to use it again later on.

Don't use Medica unless 3+ people need healing, or 2+ and its time sensitive for hitting both.

There's another post on MP issues somewhere on the forums if you search with lots of great tips.