By my third presentation, I "had it figured out".
The most important thing I did to be not-so-frazzled was to have EVERYTHING that I was going to take into the Judging Panel ready to go. And by that, I mean ALL the bits'n'pieces that would be necessary to the Presentation, and NOTHING ELSE.
When you walk into the room, you should be carrying:
* your prototype
* your paperwork
and NOTHING ELSE. Leave A-L-L your extranious stuff outside the room! (Don't worry: no one is going to filch your stuff.

)
Yes, you are alloted time to set-up, BUT worrying about taking up too much time setting up will contribute to the Frazzle Factor.
Here are my suggestions for a "clean" entrance & presentation, that may leave you with extra time on the clock:
* Take in ONLY the essentials of your presentation.
* If possible, have your prototype in one hand, your paperwork in the other. If you need to carry in your prototype in a box, have the LID OFF or the FLAPS UP.
* Start talking within two steps of entering the room. That's as far as you'll get before you are asked for your paperwork, anyway, so you might as well use that time to your advantage. As you are striding towards the Judge's Table with your outstretched hand holding your paperwork, introduce yourself & state your Registrant Number.
* Set-up your prototype on the table. Don't talk during this time = one of the Panel might start the timer.
* When you are set-up, say so: "Okay, I'm ready!" and START TALKING IMMEDIATELY. This will afford you another few seconds before the Timer is set.