How to feel comfortable giving a lecture
It made me
Nerdalicious! 
"Once you know what to say, and you know why it should be said, the obstacles are removed."
How I did it: I built up a wide body of knowledge on topics I was to talk about for long periods of time. Then, I talked about them when I was required to.
It came down to the realization that I knew things that are worth knowing and worth sharing with others.
From there, it was easy.
The key is confidence!
