(1) I read a book, which helped quite a bit: "Contact, the first 4 minutes" by Leonard Zunin. Still available on Amazon, or perhaps at your local library. Lots of good tips.

I (now) have fun interactions with people in (for example) grocery store lines, thanks to the tip that in these circumstances that you should comment on something immediately visible, so you have a shared starting point/reference point. I'll point to a People magazine or National Enquirer-type rag and say "I miss the days when there headlines about Elvis in a flying saucer", which will provoke a laugh and (often) a comment. Of course, I'm talking to people my age (in their sixties) so they remember that too. Adapt as needed to make it age-appropriate.

It also lays out strategies for how to connect in less transient situations.

As others have said, practice is very helpful.

I was painfully shy and spoke haltingly as a young adult. I'm now very comfortably extraverted.