A couple of verbal ticks, but not too many.

Humour is best left out of tech talks, unless you can poke gentle fun at yourself. I was told several times by a writing coach to make my mind up whether I was writing something serious, or something funny. Because the injection of a joke can pull the audience out of deep thought about what you are saying or writing, which might be totally inappropriate.

I particularly like the three part rule, thanks to the late and great Peter Hopwood, once of the LSE for that, some forty years ago.