A helpful email should contain at least most of the following:
- What is your phone - manufacture (i.e. HTC), type (i.e. Hero), and the android version (i.e. 1.6, 2.0, 2.1, or 2.2)
- Detailed description of what is not working. A simple "it does not work" is not detailed enough, obviously :)
- Most useful of all, a logcat. It's basically a log of what happened in your phone. The easiest way to get it is to download the "aLogcat" app from the Android Market. Reproduce whatever problem you had, then open the aLogcat app, hit the menu key, and choose "Send."
Happy bug hunting (though I'd prefer you not find any bugs, of course)!
p.s. If you are running Android 2.2 aka Froyo and you have a "Force Close," you can help by just sending the crash report to me by just following the direction from your phone!