I felt that there must be atleast one article on this, which is why I'm writing it. Of course, everything here will be as I see it, and you may have a totally different perspective, in which case, I encourage that you post a blog entry as well. :-D
Obviously, this is not necessary, but will make your experience more enjoyable. If you are a newbie to amateur astronomy, it would be helpful to read up something about observing / astrophotography (whatever you are interested in). If you are interested in observing, you should consider looking up about deep-sky objects, deep-sky observing, using Newtonian telescopes, planetary observation etc. If you are interested in astrophotography, it would be nice if you could explore the capabilities of your camera and figure out what 'bulb mode', 'ISO setting' (digital cameras, or ISO of film for film cameras), 'Shutter speed', 'Aperture' (F-Ratio) mean. There's a good chance that you'll know many of these things already if you have a camera, but anyway.
Try to figure out how to use a star chart. See if you can connect a map displayed on your computer or a sky chart to the real sky and try practising that a day before the star party. (If you are looking for free computer software you can try http://www.stargazing.net/astropc for plain Windows and http://edu.kde.org/kstars for anything running KDE)
Also try to locate some of the bright stars and well known constellations (Orion, Ursa Major) using a star chart beforehand, so that you don't waste your time learning these things at the star party.
Another reason why you are better off going prepared is because the already experienced observers (like Amar) will usually be glued to the telescope, hunting for faint 11th magnitude galaxies! Though they will be more than happy to help you out and take some time to explain things, they will not do it by default. (You can of course, however, go ahead and ask them, and they will definitely explain - but it helps to know some stuff beforehand)
Of course, this is strictly optional and you can go there with a blank face as well - but ensure that you ask someone to explain, because they may not do it by default. The very first time you go to a starparty, you might get the these-people-talk-high-level-jargon or i-will-never-understand-this feeling, which is easily avoided and corrected by doing some reading. Let me assure you that there are few difficult-to-understand 'concepts' and the jargon is trivial.
Realise that most of the observing sites we choose are remote areas, dark sites and are places that can get really cold. Therefore, you will be better off carrying:
If BAS is organising your transport, no issues. If you are coming on your own, please ensure that you know how to get to the place and preferably have a route map. Also try to avoid driving at night, because the roads are likely to be really bad. Keep sufficient time for driving - you may have to negotiate horrible roads - so you may want to drive very carefully and slowly. Try to get a vehicle which has good clearing between the chassis and the road, and avoid overloading.
Star parties are all about sharing enthusiasm, equipment and knowledge. Just ensure that your equipment is in good hands and keep an eye on them. People are generally likely to lose some part of their equipment. (I have lost a lot of Hemant's stuff, and considering Hemant's size, that's pretty dangerous! I've lost a lot of my own stuff as well - eyepieces, nuts and bolts, screws etc)
Try to stay as close to the group as possible. Avoid straying away. Ensure that you use a torch to see the road unless you know what you are doing - snakes and scorpions may be around!
Just a few points. Had no other work today and was feeling like writing something. So that's about it. If you need any help, use our contact form :-D