Advice for attending my first TCS conference
Talk to people, even if they are scary big names. 
Attend all the keynote/invited presentations.
Attend the talks most relevant to you.
Don't be afraid to ask questions.
Attend the social events, meet other graduate students, have fun.
Talk enthusiastically about your research. 
Make sure you have a 1 minute pitch describing your work, plus a 5 minute description, and also be prepared to enter into a more detailed discussion.
Ask people about their research.   Simply asking what are you working on? will get the conversation started.
Be open to possible collaborations, and follow up after the conference.