Via Google Earth Blog I came across the Google Outreach Tutorial on using Tour.
Work Flow Advice: The most interesting thing they say is that you can record a silent tour then come back and add narration later. This is very useful, I have found it tricky to navigate around in GEarth while talking to record an audio tour. By recording the tour first and adding the narration second you can make both better.
Save all your elements: However, I don't think they stress an important point: if you record a tour where you use elements such as placemarks and ground overlays you must save these together with the tour in the .kmz otherwise when your users try and run the tour GEarth will be looking for elements that are only on your computer and it won't work.