-use your PoM on CD - 11x PoM in a 7.30 fight is way too low
- Your HW:Sanctify healing is too low .. aim better with this spell/use is more effectively to get more healing (92% Overheal by 8 casts is too much)
- Your HW: Serenty is the same as Sanctify
-dont use Heal.. use Flashheal insted ..
-Your CPM seems a bit low too .. i dont know why but i cant check ur Mana over the fight (as i said i dont play anymore) but i think u need to cast more..
-and your stats are also not optimal .. u need more mastery and less haste .. try to aim at 30-40% mastery
you need to understand that your mainspells are your Holywords where u get the most raw healing power .. dont waste them on low dmg ..use them effectively
i always looked at the youtube channel "Automatic Jak" to improve in raid healing .. there are some great healing and priests guides
sorry for my bad english but i hope i can help you
like previous poster said use more Prayer of mending (nearly on cooldown)
what u casted seams fine, to cast heal is good to safe mana if there isnt someone in emergency of dying
stats not optimal (maybe a little bit shadow gear)
dont cast prayer of healing like mad if there is one Guy low Health in group 1 group 2 group 3 and 2 in group 4 - the chance u hit the right people is not very high, its no smart heal.
it depends on the fight if u know fight is short( like first boss) go all in when u know mana is no problem, if fight is long and u dont have to use ur Cooldown or Sanctify is up - cast chain POH when aoe is coming, get a feel about your mana.
and heartessence is not optimal
and maybe there were too much healers 22people and 6 healer, nearly every healer has 50% overheal or more