I've been married for 8 years so not sure anyone should care about my advice, but I wouldn't suggest going to bars or clubs at all. I know there are exceptions, but for the most part it's hard to think of an environment where a nerdy introverted person will be perceived as lower status.

When I learned to play poker, one of the key insights was that beyond the point of basic competence, literally the most important factor is table selection, and second most important is seat selection. It doesn't matter how good of a player you are if you're in a game with an even better player on your left. Similarly, you don't have to be very good to make a lot of money if you can find a terrible player and sit to their left.

I think this applies to dating and social skills more generally. While it's great to occasionally get out of your comfort zone, you're more likely to have success socially and romantically in settings where you feel in your element. The more comfortable you are and the more you're authentically enjoying yourself, the more attractive you'll appear to others. So unless you really like bars and clubs, don't go to them--or at least look for places with a vibe that suits you, not places where you feel like a loser. The best bet is to somehow find the overlap in the venn diagram of 'places/activities you authentically enjoy' and 'places where single women are present'.

They aren't always easy to find and it might take some work to arrange these types of settings if you don't have access to any that already exist, but at the same time, anyone can host a game night or book club or running group etc. and start promoting and networking to get people involved.

For some reason at the bar people don’t ever talk to me until I’ve been drinking for so long I sound like an idiot.

Seconded. And going to a bar with the goal of finding romantic partners makes you sound particularly idiotic when you loosen up a bit. That's why many approaches here, which assume rational part, especially - importantly - at the moment of human-touchness, e.g. when you're actually communicating with potential partners, can fail dramatically. Imagine you'd drink enough and start broadcasting a little your ideas which brought you - especially if you're a nerd - to the bar. You're going to have spectacular, epic what-they-say. And if you don't loosen up, you're perceived as incincere, somebody who's hiding something, likely nasty, behind them and trying to catch strangers in who knows which schemes.

intelligence can be intimidating; overbearing intelligence is almost a turn-off

maybe people are just waiting until you're down on their level

Most women aren't intimidated by intelligence. They're turned off by condescending assholes who constantly recite facts and contradict others instead of carrying on a normal conversation.

Practice sounding like an idiot while sober! ;)

I second this.