I read an article on Joel on Software last night that I thought was kind of interesting. Joel went through his first spec review with Bill Gates. What was interesting was how Bill Gates would question the person to primarily find out if the person had their bases covered. As simple as this is, it really made sense to me. The one challenge in watching over managers and employees this way is it could be very time consuming. With that said, it seems like a very useful technique for assessing a person's understanding of a problem or project.
To apply this to consulting projects, I think a large part of what happens when looking at different potential jobs is similar. I am trying to get an understanding where they are in the process and what aspects have been established and what still needs to be done.
This kind of strategy is pretty obvious, but I am finding that sometimes paying a little closer attention to the obvious can be surprisingly beneficial.