Bounce around until you find one that feels right: a good amount of regulars, people doodling, and bullshitting with baristas.
Show up a couple times a week, drop into the odd conversation. And be ready to say “anyone want to grab a beer” come quitting time.
This is just about the fastest (week to a month) way to find yourself a new in person social circle.
Volunteering. You're guaranteed to meet some good people because these are other people that are interested in (1) working together (2) helping people (3) donating their time. The very worst-case scenario is that you don't make friends, but have helped somebody in need. =)
Sports. Grown-up recreational sports are nothing like the (often hostile) world of sports you might remember as a kid. Generally very supportive places. Co-ed leagues tend to be more easygoing. If you're a beginner, pay for some lessons. For example... lots of tennis coaches out there. If you are healthy enough to move around you can learn to play a pretty decent game of tennis in not much time and with less $$$ than you'd spend on a new Xbox. Obvious direct and indirect benefits as well.
I have always loved travelling so that's what I do every weekend - to some town or hills or a beach or trekking somewhere. Treks are where I meet quite some people and they don't smoke, at least not there.
Hiking is great though
Plus all the smokers I know (not many left!) smoke outside like considerate, normal human beings so there's no way anybody would be forced to really encounter their smoke.
Smoking seems to be on the upswing among young people too.
It sounded to me like WhompingWindows is a grad student, so I heartily endorse they try this approach. Just be in public spaces more. It helps.
I’d say though that the people you meet while shooting the shit at a cafe are more likely to be “general friends” that are based more on shared personalities and humor than a shared interest. As such, these types of friendships feel/are less utilitarian