As much as I hate to, I have to agree with phil. I personally think looks are a MASSIVE factor.

So many times ive been out with some of my 'pretty boy' mates who have no game and I've charmed the ass off a girl. But I'd say about 7 times out of 10 they'd drop me and try and seduce my mate. I don't think it's anything to do with confidence and being comfortable with yourself either. The majority of my 'pretty boy' mates are insanely self conscious and don't dare cold approaching girls.