If you followed my twitter stream you would see I had started this, but figured I would post, add your own pieces to this as well.
Some of these are for small demo's, others would be for larger ones or hardware demos.
#9 - Like The Beatles said on the White album, #9, #9, #9 (ok, it was a sound technician at EMI) it's all about testing your demo and make sure it works, even after rebooting, dropping a LAN connection and logging in a someone else.
#8 - Documentation of login/DNS/IP information couldn't hurt...the alternative REALLY hurts
#7 - Backup your demo, not once, but 5 times, email it to yourself at an accessible email address NOT on Gmail, a USB device, an extra time on your hard drive, and put a copy in Gmail. What is all that extra memory space for anyway?
#6 - Drink heavily AFTER the Deno, or in the case of Lotusphere, drink regularly in moderation until Kimono's/ESPN/Jelly Rolls.
#5 - If you will be showing a demo in a language you are not too familiar with, get advice from someone that speaks the language.
#4 - If your demo is too long, you lose them, if your demo is too short you went too fast, if it was easy everyone would be doing it, so lighten up and have some fun.
#3 - Always use the same demo login/passwords, it helps so you don't have to scrap it all 1/2 way through.
#2 - Plug in the LAN Connection for devices that aren't wireless. It helps when you can't see the server doesn't it?
#1 - Make sure if you use TRIALWARE you have enough days left to use it. DOH!