If you see, hear, or read something interesting, make a quick note of it. Especially if you know it's something your friends are interested in. Use that as a list of ideas to pull from. For me this is now a mental list, but when I was really focused on improving I'd actually keep a physical list and give it a quick read before times when I knew I'd need to make conversation. Think of it less as a script, and more a menu of things that happened this week that you could talk about for a minute or two.

If there's a pause in the conversation, you can either ask a question / comment on the previous topic, or use the topic from your list that seems to fit best if it feels like time for a new subject.