The biggest signal of someone being an amateur when speaking (or writing) is discussion of the process of creating the presentation. Polished professional speakers don't talk about "when I started writing working on this presentation, I wasn't sure how to talk about X." They just put together a presentation describing the result or topic and present it without talking about all the work that it took to create. The process of creating it seems very salient and novel to the creator at the time of creation, but the audience doesn't care.
People who are nervous or give public talks only rarely will regularly fall into this trap. I think it's related to self-handicapping in presentations, but is distinct, and I have not seen it mentioned in looking at a few "presentation pitfalls" articles.
Yeah, this happens in writing too. Steven Pinker has a great name for it: "self-conscious style" (in the book The Sense of Style). That's where you insert yourself into the text in a way that's irrelevant to the subject matter.
He instead advocates that you write in "classic style", which is basically talking about X, as you say. There is something in the world, and I am going to show it through words.
He also talks about the "academic style" of writing, and has some funny examples of it. One big part of that is obscuring the prose so that you can never be proven wrong.
I think this is probably good advise in most cases, but there are rare occasions where the process is legitimately novel and fun to hear about. I'm having trouble thinking of examples right now, but what comes to mind are situations where the speaker discovered something, and it was fun to hear about that discovery.
I of course have no clue how to tell if your process story is actually good.
People who are nervous or give public talks only rarely will regularly fall into this trap. I think it's related to self-handicapping in presentations, but is distinct, and I have not seen it mentioned in looking at a few "presentation pitfalls" articles.