In addition to the typical advice of pack an extra sweater and comfortable shoes, it is also important to remember the little things, like chapstick and moisturizer. Hotel rooms are notoriously dry and while the nicer places provide a tiny bottle of moisturizer, this is often not enough. Most exhibit halls create their own wind tunnels. While this isn’t so bad on the first day, by the third your face is slightly wind-burned and your eyes super dry.
As for the comfortable shoes, even the most comfortable shoes will torment your feet after 12 hours straight. This is why it is important to bring some sort of foot soak (epsom salts and peppermint oil are great, easy and cheap).
Don’t be afraid to pack some aspirin or ibuprofen. A small bottle from home will cost so much less than what is available in the hotel gift shop. You will also want a stain stick, a small bottle of hand sanitizer and some safety pins (hems, zippers and buttons often break at the least opportune times!).
Last, don’t forget some one dollar bills. If you tip the various hotel employees, you won’t feel bad about calling when your cell phone stripped your room key and you’re locked out.