* Micromanage your pet. Seriously, manually spam that suckers heal spell on whomever needs it.
* Aetherflow even if you still have stacks left unless you have a heavy healing segment coming up. In that case save your stacks until used, then Aetherflow, then use more stacks.
*When you need to aoe heal, Rouse, Fey Illumination, wait about half a second, Succor, and Whispering Dawn. After which, top everyone off with embrace and physik's if they need it.
* Remeber that there is another healer! You shouldn't have to worry about AoE healing too much - thats the white mages forte, our AoE's are piddly and expensive. Note: This rule tends to be broken a lot during heavy healing segments.
* Eat Food. it helps.
* Mana Potions. if you REALLY need MP, buy a couple of these, and use them BEFORE you run out.
* And finally, ask the bard for a Mana Song when they healers are low mp.

Probably lots of extra stuff he can do, but that's the basics.