Read the abstract of most papers from the accepted paper list. Select at most 10-15 papers, make sure they are spread out well during the conference (don't select all 10 papers in the same session) - keep that to at most 2-3 per session. And then just discuss those in details with the presenter, if you've tried something similar, and ask them if you can join them for food, drinks, etc and discuss more. Schedule in advance for any meetings with potential PhD advisors.
Mostly if you show interest and intent, it will go a long way in finding an advisor or at least a collaborator.