Asking questions works always well, trying to understand someone's work/motivations. People like to talk about the things they find important.

strike up conversations early on. I find speaking at an event helps because it turns it into a place I belong at more. But without it, mentally claiming the space as my 'home turf' helps too. Which is why when I facilitate sessions I want to see and walk around the space before any participants arrive, so I can project my mental image of what we'll do in the session on the space.

I don't much like the premise here (preparing to strike up specific conversations with specific people) as it runs counter to the natural flow of interaction at any event (ugh 'networking event'). I do prepare though because face to face crossroads are scarce. I check who is coming that I know and would like to catch up with, I check sessions beforehand, and whether I'd like to talk to the speaker, I check for preconf meet-ups etc, and follow posts/tags about it from other attendees. That and having a set of questions and interests to guide my participation.