People are nervous to show other people their writing. It's not like this is a new discovery, or that people aren't justified. It's just interesting to see it so prevalent and first hand. I am definitely included in the category of nervous writer. People ask me what my novel is about and I get embarrassed and tongue-tied. Not good for publicity, I am sure.
So what do you do? I really don't think there's anything we can do about getting nervous itself. Nerves are nerves, whether we like them or not. In fact, I think getting nervous about showing people are work is a sign that we really care, that we put our whole heart and soul into what we are about to reveal to them. That, if anything, definitely deserves the nerves.
The important thing, though, is to not let it stop us. Yes, we're nervous, but we sign up for the workshop anyway. Yes, we're nervous, but we practice our pitch twenty times in the mirror so it will come out nice and crisp when we meet agents at the conference. Good things will come of it, and who knows, it may get easier.
So less nerves. Just write.