In fact, there's no really secure way to recruit dedicated people.
It's just like RNG again, trial and error.
One way to try it, is to do PuG-runs like already mentioned above.
The other way is to really conversate with the new recruits, try to find out their real goals in TBC (don't have to mention to not ask them directly^^), ask questions about their character / specc / gearchoice to find out if they just copy & past i.e. kungen's specc and kind of enchants / gems or if they really thought about it and decided it's the best way for them, et cetera.
Last but not least you need a bunch of luck