Additional dribs and drabs of advice
* I've found I can only attend two panels in a row before I start getting antsy and contrary. Your mileage will almost certainly vary, but consider making a list of x < 10 panels/readings you absolutely *must* go to and working around it. Flexibility is a good thing regardless.
(This might be easier once program participants are added to the schedule, though knowing that X or Y gives good panel is a matter of personal experience and preference.)
* At really good panels, I find myself wanting to raise my hand all the time. Don't be that girl or guy; there are other people in the audience. If you're really enthused and have more comments than you can decently interject during the panel, go up after: "that was fascinating, you're probably heading off somewhere, but will you be around later to talk some more?"
This works for meeting other enthused audience members, too.
Failing that, come back here / to LiveJournal / to Usenet /etc. and start a discussion about it. =>
* If I see that an author I like is having a signing, or is going to be on a panel, or doing a coffee-thing, I get an opening question or comment ready ahead of time; it makes me feel more confident. I don't bring books for signings, but I often get in lines anyway: "Hi, I don't have anything to be signed, but I just wanted to say that I like your books. Also, I was wondering [fairly specific thing, especially if there is a big line]."
* There may be two really interesting-sounding panels on at the same time. This happens; flip a coin. There may be two really interesting-sounding panels on at the same time that seem to have very similar target audiences. This might be worth contacting programming politely over (last Boskone, it was "Worldbuilding in Historical Fiction" and "Mixing Fantasy and History"; one was moved back an hour).
* Wear your badge where we can read it, please. I had a long conversation once with a very nice person who wore his badge on his belt on the side and to this day I have no idea who he was.
* The food court in the Prudential Center, in February, had quite good Indian food with *enormous* naan.
* The Higgins Armory does cool demonstrations.
Ummm, I think that's it for now.