The single most importante thing to remember is that there is no good way to do a talk. The most memorable talks offer something fresh, something no one has seen before. The worst ones are those that feel formulaic. So do not on any account try to emulate every piece of advice. I've offered here. Take the bulk of it on board, for sure. But make the talk your own. You know what's distinctive about and your idea. Play to your strenghts and give a talk that is truly authentic to you.
"So do not on any account" can be rephrased as:
A) All in all, for no purpose
B) No matter what
C) However, never
D) Therefore, do not, for any reason
P.S.>I understood by the meaning that the nearest alternatives are C and D. But, I am doubtful in alternative D on the difference between "for no reason" or "for any reason" in this context of the text.