Third, always have a back-up plan! If you are relying on websites, locate more than one site on the topic to avoid problems if a site is taken down before you teach the lesson. If you are going to use a digital camera, have a power extension and an extra battery at hand. If you need to transfer software or data, save it to two types of storage (e.g., memory stick, floppy, CD) in case the computer you will be using does not have the expected type of drive.