...and do the "popcorn trick"...
ah no...really...if being yourself doesnt work, just pretend to agree with everything she says about y'know...the typical female thing, HEAT magazine, victoria beckham, jordan, being too fat, being too skinny, fakes and "reality" tv...
nod every now and again when you're mind is really on the finer things in life, a passing waitress's bottom, whether the actors on stage ever let out a sneaky fart and what to drink next...
then if it still doesnt work out, do what markdini said...give her the bill...i always add an emotional service charge of at least 17.5%...and then pinch her bottom and run away...
EDIT: meant to say, genuinely, just be nice, make her laugh, give her hand a quick squeeze and always offer to see her home...even if its via binoculars...