Learn to sing, if you're fortunate enough to have a naturally appealing voice. It takes less time to become moderately good than it would to learn other instruments. Hit up karaoke bars where college girls/young professionals congregate. Belt out the tunes and blow all the other posers away. Being in front of an audience regularly would probably also help improve one's approach confidence in general as well.
This strategy worked extremely well for a buddy of mine several years ago - he usually sang vocals for metal bands, but in his free time he learned to do perfect covers of pop, boy band, etc. tunes for karaoke. He'd go a few weekends a month, to the point that he became a fixture at the local places and people would look forward to seeing his performance. He'd pull contacts every night he was there.
This strategy worked extremely well for a buddy of mine several years ago - he usually sang vocals for metal bands, but in his free time he learned to do perfect covers of pop, boy band, etc. tunes for karaoke. He'd go a few weekends a month, to the point that he became a fixture at the local places and people would look forward to seeing his performance. He'd pull contacts every night he was there.