Re: 3, it depends on the kind of demo. Recording a video demo is a great backup, especially if your demo needs internet and the conference has flakey internet.

Re: 3, it depends on the kind of demo. Recording a video demo is a great backup, especially if your demo needs internet and the conference has flakey internet. However, if you rely too much on demos, it can give people the impression you don't have faith in your project. Re: 8, one trick, depending on the size of the audience, is to ask someone to tell you when 20 minutes (or however long) have passed. People are happy to help, and timing like that can help you speed up or slow down your talk if needed.