Present the Subject and make sure it’s the right one!
Make sure that the subject you are speaking on is suitable for the audience, so do your homework. Find out something about the people who will be listening: age, sex and even any background information you can glean from the secretary of the club/ society/school/church/company etc.
I remember a talk given by a BBC gardener to a gardening club I once belonged to. The club consisted of many people who grew vegetables for consumption, there not being a local show at which to show them. Many of the members had allotments and were proud to be self-sufficient in vegetables.
The BBC gardener (who I will leave nameless- but this is a while ago and he is not on TV now) spoke only about show vegetables, all of which were enormous and impractical for the kitchen. He had a slide of an enormous onion. Without waiting for the question period, one elderly local shouted out, ‘What the dickens would my wife do with a gert big thing like that?’
The BBC man was completely flummoxed and had no answer. He had assumed that his fame would mean his talk would be appreciated because of who he was, no matter what it was about. Immediately, other members joined in a chorus of how silly they all thought massive vegetables were and how lacking in taste. It was embarrassing for all. The BBC man should have asked what sort of a club it was and if his talk on Show Vegetables would be appropriate. On TV he was regularly seen growing a variety of things, including vegetables and a broader spectrum of gardening information had been expected. He didn’t come cheap and it was an expensive mistake for the club.
One key point about giving a talk or presentation of any kind is to present the subject, not yourself. If you present the subject well, it will tell the audience much about your personality, abilities, confidence, sense of humour, interests etc but keep yourself in the background of the actual presentation. If, for a job you need the interviewers to see you, let the presentation do the work for you.
If you are a retiree with a lot of experience, bring out your personality in presenting the subject you have been asked to talk about. Let people ask you about yourself afterwards.