davidr, 
I've got two recent grads in my group under my de facto...mentorship? Command?
They are both very smart. One is very confident he can do things but is less effective, one is less confident and more effective.
I'm very unused to constructive criticism and other #leadership skills so I'm not sure how to turn down the confidence and turn up the effectiveness.
I mean, I know what to do. "Test. Be skeptical of your own work/ideas."
I don't know how to say that.