I can't believe that the PUAs haven't leapt all over this thread by now!
Short version: It's natural to develop 'oneitis' when you don't have a lot of romantic experience. The cure is to have a lot of romantic experience.
Then you'll realise that a given girl may be unique, and
that there are a lot of other unique girls out there.
Or so I'm led to understand - I confess to being an AFC myself...