Tape your mouth when you sleep, when your body thinks it's about to suffocate your nostrils will open right up.
Make sure your tongue is pressed up on roof of mouth right behind your top front teeth when you are awake, keeps you breathing through nose and not mouth.
Go to the gym and hit the treadmill, run as long as you can only breathing through your nose, go back everyday and increase the time by 5-15 seconds.
...
This combo solved it for me and got rid of snoring.
When I started on treadmill I could only do about a minute of running without mouth breathing, now I can go as long as my legs will last.
Don't expect to be able to make it through whole night with your mouth taped, and tape verticle not horizontal, with small easy to remove tape... don't kill yourself.
Fur Elise wasn't discovered until 40 years after his death and its unknown who it was written for.