One of the hardest parts of producing is trying to get the best out of an artist. As Rokket indicates each artist needs to be handled in a different way. When you read various artists comments on producers it is intersting how important the rapport is and it is even more interesting to hear what producers say about the need to "stroke artist's egos".
I try to stay very positive such as "That was a very good take, your tone was great, but I think you could be better on your articulation" or "I think you're getting better each take, let's try one one, I'm betting you'll ace this next one".
When all else fails, I do a playback and simply explain where improvements could be made - and hope that artist has the ears to hear the truth!
