So, i dinged 85 with all of my 5 toons a few days ago and noticed the "You need a higher item lvl to enter this dungeon - 329 required." for Heroics, so i decided to do some AH shopping and a few 85 normal runs.

Shortly after i got my 329 minimum i went to do the(pre patch), said to be easy, Vortex Pinnacle.
Simply put, i got raped by the first boss. It was all easy and so, but when he had about 500 000 - 1 million hp left i found myself starved on mana on all of my toons..

So question is, when did you start doing heroics successfully, without getting oom before the combat is even near to finish?

Is there any "advice" on how much mana / sp / dps etc. i should have before i start?