In the past, I have always "coached" people. I like to think that I can spot a raider that can be good if given the proper guidance. Raiders that, say, are great at being raid aware, but their DPS just isn't up to par... simply because they aren't tracking self-buffs properly or their rotation is slightly out of whack.I prefer coaching. For example, I have been playing a rogue since vanilla. My brother started playing at the beginning of cata. He picked up pretty quickly on the basics of a rogue, and is pretty decent at awareness, but MAN did his DPS suck, even after the recent patch. He's been a gamer as long as I have, and I know he's not incompetent.
I pulled him aside, with my rogue, and (I moved into an extra room at his house recently), said "watch what I do." I explained why Assassination needs rupture, why you shouldn't clip envenoms, why using something like weak auras is good to track them and why that's important. Then we sat down and beat on a dummy together and compared recounts. Spent about an hour doing this. Last night in a DS run, on ultra, his DPS went up by 10k.
Both in game and when I am in a leadership position at work, I'm a firm believer in trying to get the person to improve before getting rid of them. For in game, saying "go read EJ or MMO-C" can have some results, but doing things like pulling them aside won't always have good results. Pulling people aside and talking it through with them seems to give me some decent results. It's actually quite nice when I watch someone go from middle of the pack to always topping charts just because of something I talked to them about.
So, when you have a raider that you know could be good, what do you do? How do you handle it?