Someone asked me today what my "Conference 101" would be. This is what I told him, with some extra commentary.
You want to be close enough you can actually see the speaker's facial expressions. It's hard to remember and stay engaged with a person who looks an inch tall next to some matchbook sized slides.
Talk with everyone
In general, the speakers are talking to you, not with you. Speaking with peers at conferences is one of the best way to find out about the real-world uses of things you might be looking to implement. You could even help someone out by telling them your horror stories. :)
Take relevant notes
Write what's relevant to you. Don't copy everything the speaker says, or has on their slides. The speaker will probably publish their slides online if you need to refer to them later.
Be careful comparing yourself to speakers
Speakers are giving you their highlight reel. Be careful comparing yourself to that. It's easy to think "These people are all so much better at this than I am", but that's not fair to yourself. Take what they're saying, aspire to it, and adopt what makes sense for you.
Be awesome to everyone
Which is just good advice anyway :)