Gemming/spec look alright? I did some reading from elitistjerks and that is what I understood from what they were trying to say.
When I am healing heroics, I notice that perhaps i'm not using the right 'rotation'. I have a hard time distinguishing when I should use divine light versus holy during high damage. I use holy shock whenever it's off CD or when I have the tank at a decent amount of health during high damage situations. I judge whenever I have a second, and usually use WoG if group doesn't need LoD. Any suggestions?