With CFUnited around the corder, here are my tips for having a good conference.  I'd love to hear your tips as well!

Attend Sessions
And by attend, I mean, really attend sessions.  Sit near the front and focus on the presentation. Turn off email and Twitter.  Take notes with a laptop but try not to use it for anything else.  You'll get much more out of a session this way.

Talk to Everyone
Talk to as many people as you can.   Personally I find this one kinda hard since I'm somewhat shy but this is key to getting a lot out of a conference.  I'm going with a huge generalization here and come up with three groups; 1) those more advanced than you, 2) those at your level or more junior, 3) exhibitors.  You should talk to them all.  Here's why:   Group 1 will help expand your knowledge.  Group 2 will help expand your knowledge as well.  Wait, you may ask, how can those more junior expand your knowledge?  Because growing as a developer is not a simple ladder that you just move up one step at a time.  A developer of six months may have focussed exclusively on one area and be able to give insights on that.  Likewise for both these groups you can provide insight to them.

The final group, exhibitors.  Go talk to them.  Sure some will be a little pushy and sales-ey but you will gain knowledge of what they do.  And while you might not need them now, knowing what they do can help in the future.

Be Nice to the Organizers
Having worked in the background of conferences I can attest how much works goes into them. And also how much work happens during the conference.  Pretty much the whole time you are awake at a conference they are working.  So be nice to them and patient if something goes wrong.

Relax, Have Fun and Learn!
I don't have much more to add to this one.

What are your tips for having a good conference?