Talk to every single female you meet whether you're interested or not. Just to get used to small talking.
I'm in the same boat as you. I've been to a few meetups, and what's been said in this thread is true, if they're worth dating, they wouldn't be at a meetup unless they're genuinely interested in the event. That said, if you want to practice chatting with girls, meetups is great!
Random meets!
Places where I found success in meeting datable ladies; mutual friends, doing stuff that I like doing, day trips (like tourist day trips), school, work (really depends on your type or work, eg nursing vs construction), flirting with the waitress, and various conventions.
Potential place, public transit, still working up the courage to do cold approaches. I forgot to mention, church. I'm not christian, so I wouldn't know, but I know of a lot of people that have met through church.