I got over the "stage fright" of throwing in front of people and being self conscience about my throw by playing in a random draw doubles league. You can learn a lot from the people you are playing with, and you also realize even the best players have some awful shanks occasionally.
I was about to post the exact same thing. We used to have a pretty casual random draw doubles, with players of all skill levels welcome. It was a great place for new players.
In addition to all you said, they would soon find that there are other players who are just as bad.
And it helps the ego to be able to discard most of your worst shots.