And as has been discussed around here before, (1) confidence is an aphrodisiac, and (2) desperation is the worst cologne.
I am no better looking than I was as a yute, and I was no calendar boy back then. BUT, I have the confidence of a successful man of my age, AND I have no pressure when talking to women because I'm already locked down. So, do I chat up and flirt with women? Absolutely, it's fun as hell. I do it at the grocery store, the bar when I'm traveling, all the usual places. And my casual I-don't-really-care confidence works wonders. On more than a few occasions, I've hit the "oh shit, I better wrap this up, because it's working" point. Which made me realize it is actually remarkably easy to pick up a woman in public. If average old me can do it, anyone can. It just takes some social and emotional intelligence, and unbroken confidence.
The problem is, confidence is gained through experience. And these guys don't have any. Which makes them mousy cowards, which keeps them from getting the experience needed to become confident. Step one is "stop being a pussy, put yourself out there, and man up and don't worry about rejection or falling on your ass. Just get up and do it again and again and again.
She just rolled her eyes and walked away? Cool. Go up to the next gal. And then the next one.