do's and don'ts of networking for a PhD student in a conference?
One could easily make a long list of obvious don'ts relating to basic conduct at the conference.  However, given your stated goals, here are some things I would recommend:


  Do present your own work in a clear and simple way that allows the audience to understand your topic and get interested in your problem.  Be prepared to discuss your problem (and other research interests) afterwards and form collaborations if you find them useful.
  
  Don't try to impress people by making your talk sound complicated - make it as simple and clear as you possibly can.  Impress people by your clarity rather than trying to bamboozle them with complexity and obfuscation.
  
  Don't restrict your goals to meeting only the "elite" researchers.  Try to network broadly and talk to anyone else who has shared interests.  Focus on talking to people who have shared interests with you, who can have a clear and fruitful conversation with that imparts value.  You might find that your most fruitful interactions are with people closer to your own research level rather than the most elite researchers.