Let me try again: try night clubs that play music you like; that helps a lot in winnowing the playing field and showing women of the type you'd enjoy dating.
But hey, we're talking flirting, right? Finding fuck-friends is probably easier with dating apps; and maybe one of those even converts into a sweetheart. Flirting is really fun though.
Music I like? I've never heard of a night club that plays 80s thrash metal, 70s hard rock, etc. It's always some horrible dance or pop music, or country. I also don't drink (except maybe a half-glass of wine on rare occasion with a nice meal at home), so I really don't see how the nightclub scene is any better at finding someone I'd enjoy dating than a dating app, in fact at least with the dating app I have a chance to find women who aren't alcoholics who listen to shitty music.
So instead, I've been trying (during better weather than current conditions) hiking groups on Meetup.com, since I do like hiking a lot, and would like to find a woman who also enjoys hiking. That hasn't gone all that well; it seems most of the people in these groups are retirement aged. I do see age-appropriate women out hiking, but they're usually with a husband/boyfriend, not in one of these groups. AFAICT, the single women in the age range I'm interested in (30-45) in this area (DC) are not into hiking at all, but they are into getting drunk from what I've seen of them downtown. And from what I've seen on dating apps and OKCupid, the ones who aren't downtown socialites are mostly Trump voters who spend their weekends at the gun range.
