Ghostbusters II (1989)

The Girl: Janine Melnitz (Annie Potts)
 
The Geek: Louis Tully (Rick Moranis)
 
The Technique: You'd think Louis would've been happy with (possibly) bagging Sigourney Weaver's Dana in the first one -but he was possessed during that, so he doesn't remember and it doesn't count.

Eventually, it's his heroic backing of the boys and his unsure nature that attracts Janine (no superstar in the confidence stakes herself).

One babysitting stint later and the pair are at it like rabbits, so maybe you should offer to babysit and leave spook-hunting to the professionals.

Next: Superbad