I often see the advice "Ask people questions – because people love talking about themselves" and people try it and say the conversation just dried up.
So what's going wrong?
Basically it's an ill-founded premise. Most (but not all) people enjoy talking about "themselves" only in the sense that they want to talk about their interests. And these are things they are passionate about. So that might be their love of architecture, their love of travel, their family, fashion, model trains, crossfit, etc.
So, if you ask "what did you do yesterday?" and they say "Oh, I just went over to hang out with the kids flying kites, and then to the gym".
And you get annoyed because they haven’t kept the conversation going so you ask
"Are those your kids?" and they reply "no, my kids are grown, its my grandkids"
and you get stuck and decide to bail on the conversation – what has happened is a deep misunderstanding of WHY people love to talk about their interests. People are inherently social creatures. People are always looking for their tribe. The point of questions is to find your common passion
Their answers are them showing their interests, these are connection points. So the point of your questions isn't to "get them to talk about themselves" it's to (as quickly as possible) find a common subject that you can bond over and share a passionate conversation.
EXAMPLE you ask "what did you do yesterday?" and they say "Oh, I just went over to hang out with the kids and then to the gym".
You say "are you doing anything in particular at the gym? Ive just been getting into cycling but its hard on my knees"
They might say "Oh I was training for a triathlon but I'm doing physio stuff now because my hamstring went, so I can empathise"
You say "So, you were cycling a lot then? Are you still cycling?"
— now perhaps that cycling thread goes nowhere, they actually hated cycling, so you try a different route. If a topic is obviously not one they care about, pick up an earlier thread they dangled. "Grandkids you say …", "kite flying …" , etc. flip through until you find a niche close to one you love.
"Oh yeah, I like kites because I fly gliders" , "Oh wow, I'm just doing my pilots license !"
The key is to find something that you are BOTH passionate about. It needs to be a medium sized niche. You don't have to share their exact passion, but something close is what you want. So the fact that they love "music" isn't really good enough, but if they say that they play bass and you play violin, that's good. If they are into "exercise" that's no use, but if they are into Bouldering and you are just starting top rope climbing with a friend – that's good. Etc
So. tl;dr
the point of "asking them questions about themself" is to (as quickly as possible) find common ground where you can both bond / disagree about nuances. People love to talk about their passions, and connect with other people who are interested in similar passions – so they can bond.