Until such time as you can implement auto-saving notes (which would be ideal),

Please create an intuitive keyboard shortcut to save notes (e.g. "alt+S").

If you could also make the default "alert" when you leave a note without saving it to be "YES SAVE THIS NOTE" instead of "yes leave this note without saving," too, then you would have something almost as good as autosaving (tho autosaving would be ideal).