The thing with using opinion openers in clubs is not the
fact that they don't work, it's about how the target
complies with the question you're asking without
making it seem like you're hitting on them
or trying to pick them up. Think about
it like this. The second the girl see's
you coming directly to her she'
already thinking "Oh god,
another guy coming to
pick me up..." That's
her first response towards
you and that will trigger a bitch
shield against you.
Lets say you do ask her the opinion on whatever
it may be and she's thinking now "He came
all this way to get my opinion on something?
He's hitting on me"
You've got to come under the radar and penetrate her
defences better without looking like your wanting to
get with her in some way. The best way to
go about this is to build social proof in the
club/area...wherever, make friends with
small groups of people in that area so
she can see that people know you
and you are friendly and at the
same time she'll be thinking
"Hey, why does he know
everyone in here and not me? I'M
THE HOTTEST GIRL IN THIS PLACE?! How
can he not know me

" She will then
be more inclined, if not attracted to
you indirectly just by not approaching
her at all.
You get me? By building up the social proof
value around yourself you will attract girls to
you because you seem to know everyone in
the venue except them...and they want
to know who you are, this then causes
PRE-SELECTION! Ahhh...you see what
i'm getting at?
My advice, scrap the opinion opener.