I dont know what difficulty you are playing on, but I consistenly are top healing and very low in over healing. Here is a few pointers that I play by when healing normal EN:
– Healing Rain up all the time.
– Chain Heal for them big bursts
– You dont always have to pop both CBT and HST at the same time
– Use your totems intelligently (e.i. know the fight and when to pop them)
I know these pointers seem obvious, but its what differentiate me from the rest of the healers.
We shamans have so many awesome CD’s to blow and doing so all at once is just a complete waste of healing. =)
Before I go, let me give you an example;
Strat: Pop CBT (Cloudburst totem) well ahead of the charge, since it deals a massive amount of dmg to half the raid. Then right after the charge you activate the gathered healing and boom “heals, heals everywhere”. This is a very simple strat and makes a ton of difference =)