The way to be Confident.......

The way to be confident is to act confident.
I take it to another level. I get my "students" to pick a film star to play their life story. They are now going to do the scene the student has been dreading, eg the big presentation, or the cold call phoning, or whatever it is that makes the student nervous.
The student now has to imagine how the actor feels about playing them. The actor is not nervous. It's just part of the job, there is not the emotional baggage. It can be played without trauma, because the actor does not feel this is his life under the microscope.
Now all the student has to do is play the actor playing them.
That is often my starting point for nervous people. We then role play it out until acting confident starts to become natural.