I recently did a blog post for The Ohio State University Libraries Teaching & Learning blog, giving some tips, and new practices to bake into your habits that can help you when you run into the worst case scenario, flaky internet, your database being “down for unexpected maintenance” right when you are ready to demo, or the internet just plain going out.
Check it out here https://u.osu.edu/tlmaterials/2019/02/08/the-internet-is-down-how-to-succeed-in-an-unexpectedly-low-tech-classroom/