I have experience as an industrial trainer and teaching tertiary students and completed a TeFL course in Phuket. I was particularly impressed by one of the tutors on the course
who conducted demonstration lessions and hardly spoke a word - it was as if a female Marcel Marceau was in the class and the students loved it and the response was amazing.
It was one of the best displays of teaching I have seen and a brilliant example of the power of silence and non verbal communication.
When I started in sales many years ago I was told "they will never know just how dumb you really are unless you make it obvious". Don't worry about making mistakes - that is what learning is all about and if you can make things fun you can get away with heaps.
I do voluntary work teaching Thai migrants and they are great and love to have fun.posting.php?mode=reply&f=11&t=2988&sid=50c9d55871a0bbc51369c8cf14abbebd#
Good luck, a half decent training course will provide you with the skiulls and experience to build you confidence.