Ohhh good luck!!!
I just got a job offer last week to do convention and tradeshow planning. I'm very excited, I start on the 26th!!!!!!!
I agree with the dressing up part I think it helps. Just to get you in the right mind-set. I would suggest making sure there is space at a table or a desk to sit at and take notes, (like the names of the people on the conf call), maybe a small glass of water just in case. Other than that, just make sure you use your voice to express what your hands do and you'll be great!
Good Luck!!!