I think using names when referring to people is a good trick in a group excercise; ask their opinion on something and then when they reply, say 'yes, that's true' or 'yes, that's a good point' and then add something to it. I was criticised for not building enough alliances with others, although I guess it's hard to do that without appearing like you're ganging up on someone!
I personally think that the buiding productive relationships skill is really useful and important; a guy in my group at the FSAC was very rude and aggressive, and seemed to be actively trying to start an argument with a couple of other people in the group. Although most of his points were probably the best that any one of us made, the way he put them across just made the whole thing feel really uncomfortable. I'm not suggesting that anyone here did that, (this guy was definitely an extreme case - at times he was so rude I wondered if he was an actor who'd been emplyed by the FSAC to see how we coped!), but it just shows that the way you put ideas across is just as important as what those ideas actually are.
I know a few people who attended the FSAC, and it seems that in the group exercise, nobody got quite the right balance - either they were very good at taking the lead and coming up with ideas but weren't seen as including others enough, or they were very positive, encouraging and polite etc but not forceful enough. It's hard to get it right. It's quite interesting that in my experience, most of the guys were the former and the girls the latter - not trying to start a debate on gender stereotypes here, as I'm sure there are plenty of exceptions to the rule, but I do wonder if there are trends in how various groups of candidates perform at FSAC; male/female, younger/older etc.