I'm not going to go over all the reasons why ideas like church or running clubs are bad ideas.
The real list, in rough ordering of most to least effective.
* Online dating. You're just not maximizing your dating options if you're not using dating apps/websites. Even people who are very attractive, would have plenty of options present themselves in real life, use online dating to maximize their already-abundant options.
* Social media. People are meeting through mediums like Instagram. It's like an online dating app in disguise.
* The workplace. It's so often that I see on Facebook or LinkedIn that one of my previous female coworkers suddenly has the last name of a previous male coworker. Another thing is if you have a job such as in sales or bartending and are interacting with people all the time, you'll meet people through work who aren't your coworkers.
* Bars and clubs. If you're socially competent and can manage your alcohol consumption, this is not a bad option in big cities. There will be women in their mid- or late-20s, maybe even their 30s, who moved to the city for a job or who are still in school getting a post-graduate degree. I know professional guys in their late 30s who are dating women post-graduate students in their 20s who they met at bars.
* Travelling. Being in foreign countries seems to naturally lead to more conversations with strangers who are in an adventurous and social mood. Also, as a Western guy, you have a high value in places like South America or Asia.
Use a match maker. You do not need to be rich or even good looking. There entire career is helping peopleake connections. They will help you narrow down who and what you are looking for. If it works or doesn't work you do not have to tell anyone how you met. Keep an open mind about it. Don't stress over the stigma. The scandalous details of how I met the mother of my kids and now wife were not shared with anyone. When it comes up we always answer, while hanging out with friends. No one cares. Good luck
Dating in your 30s is very easy. I met my wife when I was 34. A combination of online (match for me) and meeting women while our was like shooting fish in a barrel.
Plus in your thirties or even older you can still date girls in their 20's
Sure, it happens sometimes. Buy your dating options are still fewer as you get older.
The age range of women who would theoretically date you does increase over time (e.g. in high school it was rare to even see a Junior dating a Senior, and still it was uncommon in college to see a Freshman dating a Senior), but that increase is more than cancelled out by the fact that the number of attractive, single women in the range decreases over time.
The women who are in their mid-20s going out with a guy in his 30s are usually not the most attractive women. If they had enough options, they would be going out with a guy their same age who had whatever characteristics the 30-something guy had.
Couple of wrinkles: I'm generally attractive to women so their receptive body language makes it easy enough to strike up a conversation like you would with anyone while out and about. But I am pretty particular about any woman I'd date now in my 30s (lots of drama and chaos in my 20s) so a lot of these women don't really light my fire.
How do you break the ice?
"Hi, you seem interesting, what's your name?"
Then point out something you like or are interested in about her and/or the situation. At some point, in an appropriate manner, convey that you are attracted to her and would be interested in pursuing some sort of romantic relationship WITHOUT seeming too bought in at first, give her a chance to sell herself to you as well.
When you first start, dating is a number's game and you only have so much influence on each girl you meet to pursue whatever type of relationship you're looking for (due to variables like relationship status, sexual orientation, geography, ect), so worry less about the quality of each initial interaction and more about getting yourself in front of as many women as possible. In sales, you wouldn't be just worried about each individual buyer before you even have a sustainable pool of leads to choose from.
Also, as a side-note, I would not go out of your way to meet women at work. Too risky with more drama than necessary, work is already stressful enough without romantic drama being added to it.
Couple of wrinkles: I'm generally attractive to women so their receptive body language makes it easy enough to strike up a conversation like you would with anyone while out and about. But I am pretty particular about any woman I'd date now in my 30s (lots of drama and chaos in my 20s) so a lot of these women don't really light my fire.
You forgot the most obvious one that provided as much opportunity as all the ones you listed combined (including the indie concerts)…
Church
So much at church.
I was about to write something about making sure you respect that religion first, but then I realized I met my own future wife at a church outing. However, we were both still under our parents’ influence at the time, rather than into church ourselves. We still married in the church, much to our parents’ satisfaction, but we left together eventually. So, yeah,… church.