[tokai]

Defensive pessimism have worked for me in the past. Convincing yourself that the event is already over and have failed. The deal is done, you don't have to fear your failure - you have already thought through the consequences of failing, and have accepted that you will have to face them. The actual speaking will just involve going through the already determined motions.

This, I find, can give some relieve from the most debilitating effects of anxiety during speaking.

https://en.wikipedia.org/wiki/Defensive_pessimism