The main ingredient, at least for me, was being determined enough to push through the discomfort. A lot of the early interactions were awkward, sometimes overtly uncomfortable, but that's an unavoidable part of the learning process (and I took a key lesson from it - it's okay to look like a dork, usually it's only our inner critic that turns it into an immortal sin).
Nowadays I feel a pang of sympathy when I see someone feeling shy or speaking in self-deprecating terms. I remember how that felt, and I remember how easy it would have been to have stayed inside that box for the rest of my life.
Glad I didn't.
How do you know what to say?, usually I can start the conversation but I don’t know where to take it after. How are you able to shift to the next stage when you have both agreed that the weather today is nice.
How do you get over the feeling that you are wasting their time?
Finally, how do you end the conversation when you're still going in the same direction or waiting at the same place?
Note, rather, how friends converse and how little scripting is involved. When two good friends meet they don’t say their profession, or academic rank, or ask interrogatory questions. They exchange enthusiasm for each others presence and the conversation tends towards exchanges of perspective/experience and reflection thereof. Statement, vibes, counter-statement(?), more vibes.
That kind of familiar, friendly, approach to conversation is always available and short circuits the scripts. It efficiently probes for people who want to talk and what they want to talk about. It also tends to involve a lot of dumb-yet-charming assertions about the current situation, which takes awareness not planning. A ‘sense’ of humour, not a tight 5 locked and loaded. “Fuck, now that’s a lineup…” isn’t a refined piece of social engineering, but it’s a serviceable conversation starter and the least important part if you’re still talking three hours later.
If they are open to small talk, they will drop some tidbits that you can spring off on. Conversation is a two way street. If they don't seem interested in keeping the conversation going, tell them to have a nice day and carry on with yours.