I don't have friends I have real live conversations with. Text only. For acquaintences/coworkers:

• Common topics: past/upcoming weekend, past/upcoming holidays, past/upcoming vacations, pets or children or family, general problems they're dealing with, interesting projects at work. Anything they've brought up tends to be fair game.
• Real key skill is to get them talking about something. Something passionate or strongly felt/emotively connecting topic. You don't have to connect with them, only their feelings matter. Then you can keep the conversation going with absolute minimal wording. Once they're talking, repeat back some of their own words. This prompts them to keep talking and makes you look like a great listener. E.g., person shares a story about how their dog injured themselves and needed an x-ray at the vet. "Oh, Pookinz needed an x-ray?" Makes you look like a great conversationalist, doesn't require a lot of cognitive load, and keeps the talky-talk flowing smoothly. Feels dumb as fuck and I don't like it -- but it works.
• Sometimes silence is a sufficient prompt to get people talking. People don't like silences and will eagerly fill them. Noted, silence is awkward and people will remember the awkward. Use sparingly.
• Reveal as little as possible about yourself so you don't have to talk about private things that make you squirm. People mostly wait for their turn to talk rather than actually listening. So it honestly doesn't so much matter what you say about yourself unless you're seeking a genuine connection.
• Last key skill is redirecting or escaping the conversation without seeming like you've pressed an eject button. Nothing rude about "so, work time..." or "I hate to yank us toward productivity" or even turn it into a little bit of an existential joke -- "Sorry to draw us all back into the eternal work-slog."