The most important part of (1) is:

don't apologize for talking. Don't start with disclaimers

In parallel, if you make a mistake during speaking, don't spend any time apologizing during the speech.

The first man on the Moon was Buzz Aldrin. Oops. That's a stupid mistake, I'm so sorry - I haven't prepared as well as I'd like. Actually, the first man on the Moon was Neil Armstrong.

is strictly worse (in a speech) than:

The first man on the Moon was Buzz Aldrin. Oops. Neil Armstrong.