Being a raid leader is very hard. Lets not even bring scheduling into the mix and recruitment. Let's say you already have all those things done.
Like Sutekh said, check your ego at the door. Rage doesn't do shit to progress a guild through the ringer.
You need to know how each class in your raid works. What kind of DPS they should be putting out with their Ilvl, what kind of utility they bring in their spec, and what kind of defensive CDs they have and if they are using them. I complete must is downloading and using worldoflogs software from worldoflogs.com
Without this software you won't know if people are doing things right without going into your recount or skada or DBM logs.
Critiquing people should be done very generously, but very friendly. If somebody doesn't know how to play their class teach them. If somebody can't get out of the fire, try to practice with them at the brawlers guild. You need to put extra hours in.
Lastly, do not raid with clickers.