A few things that I have learned regarding building an app in MonoDroid that I need to remember.

• Don't try and edit a user interface on your own.  Use DroidDraw or some other tool.  If you don't you will screw it up.  If you go decide to edit by hang, you should at least validate the xml file that contains the user interface.
• If you get an error like this one:
  Error 1 System.InvalidOperationException: Command failed. Command: C:\android-sdk-windows\platforms\android-8\tools\aapt "package" "-M" "C:\Users\WALLYM\AppData\Local\Temp\si5rzzgo.xf5\AndroidManifest.xml" "-F" "C:\Users\WALLYM\AppData\Local\Temp\si5rzzgo.xf5\resources.apk" "-S" "C:\Projects\MonoDroid\softkeyboards\softkeyboards\obj\Debug\res" "-I" "C:\android-sdk-windows\platforms\android-8\android.jar" C:\Projects\MonoDroid\softkeyboards\softkeyboards\aresgen softkeyboards
  It typically means you mucked up the user interface.
• If you get an error that makes no sense, try turning up the MSBuild output verbosity level.
• You can use the ADB android debug bridge.  You can run it in a window and output to a file to keep the values around easily.
• ADB is built into MonoDroid.  Its in the "other windows" in Visual Studio 2010.
• If you are debuging on a physical device, make sure that you plug your device in and have it on a wifi network.  Yeah, this sounds funky, but I've been told its true.
• If you get something like the following error:
  
  Just do what it says.  You are screwed.  Close your Visual Studio session and then reload it.