I'm a firefighter and recently took a 2 day Instructor Methodology course so I can get my Fire Instructor 1 cert in the future. It was a really good class, and I learned a lot about communicating and teaching which I think can apply here. I definitely know the fear you're talking about; the first day we were required to do a 5 minute presentation on how to do something...anything. I chose something fire related: taking apart and cleaning an SCBA regulator. and boy was I jittery! I could barely get the top cover off and my buddy had to hold it for me. If I was any shakier I would've stabbed him with the screwdriver I was holding (remember this, it's crucial to what I'm going to tell you to try).
But you know what? That five minutes breezed by so **** fast.
The next day we had to get with a partner and arrange a 20 minute (TEN minutes each!!) presentation on a fire topic.
I found a good way to eliminate that initial stress, though: Confront it right off the bat, and set it up to intentionally get a laugh out of everyone. You do two things here: You play it off as a small thing, you laugh at it yourself, and you get your audiences attention and confidence in you by showing you aren't afraid anymore.
As I was setting up my slideshow and projector, I idly talked to the class to get more comfortable. I started off with this:
"Well, since yesterdays presentation was on how to stab suchandsuch with a screwdriver, I WAS going to do today's on how to hit him with a hammer. But they said we had to choose a fire service topic, so that didn't play out."
Everyone laughed.
This did a few things:
-It showed them I could joke around and had moved on.
-It actually helped me move on, because I -did- laugh at it.
-It got my audience interested, because the last four presentations had them all snoring. This gave me confidence.
Lastly, it ties in to a good old adage: If you can't make it, fake it till you can. Eventually you start believing yourself and then you have the confidence for real.
You do need to pick out a topic to talk about, though. What do you like to do? Do you ride a bike, do you know about computers, know about cars? Is there something you've been thinking about? Be frank. Be honest. Don't be afraid to talk about certain things....one of the guys in my Methodology class did his 5 minute presentation on how to properly spend a whole day playing video games. He even brought in a controller and some other stuff for props! People loved it because he was confident, and he made us smile. Another guy did his on how to make good holandaise sauce for eggs benedict. It doesn't matter...most adults come to the realization that everyone does different things, and there's none of these contrived 'schoolyard' reasons to reject people because of it.
Pick your topic, or at least find one to start developing as practice. You'll want to open up Wordpad on your computer and write a short bit about what the topic is. Then, under it, come up with several 'talking points'. Details to discuss. With only 90 seconds, this will probably be easy. Then, practice introducing yourself and your topic and go over the talking points.
Here's an example from my 5 minute presentation of what I would've jotted down. You probably don't know about what I'm specifically talking about, but just note the components of the layout and the thought process:
'How to Clean an SCBA Regulator'
-Reason why: A clean regulator lasts longer and functions properly; we take care of our equipment so it'll take care of us
-Process: Remove the cover, remove the diaphragm, wipe it clean and air-dust the inner mechanism
-Lubrication: Explain the Cristolube, where it comes from, and WHY we have to use that specific substance; smear it on the diaphragm
-Explain and demonstrate reassembly
Through all of this, with just those four 'discussion points', I came right to five minutes.
If you like, Lebowski, once we've got you a topic, I can send you my cell # and this evening (it's 10:15 AM right now here in Idaho) we can actually do some phone coaching. It might help you to run over it once before class, and I can give you some pointers.