To be a good listener. Try not to express our own views too early or otherwise this would just prevent them from telling us the full picture and their feeling.
At most we may just help them to analyse their question/situation, building up scenerio for them to visualise the outcome and let them make their own choice.
Even their choice may not be the best choice, we should not stop them right on the spot. We may as well monitor closely and create opportunities for another discussion with them.
Just to share my own thinking and I'm not sure whether it works all the time.
Regards,
toffeeli