This post has been inspired (if that is quite the word I'm looking for) by my attending a few events that were less good than they might have been had the speakers obeyed the following rules.
Say your name (and website) clearly
If you don't have slides (why not?). at least say who you are clearly. Even if it's a niche topic, not everyone will know who you are. If someone wants to look you up afterwards to view your work or follow you on social media, please make it easy for them.
Don't mumble
Closely related to the first point, this refers to the annoying habit that some speakers have of allowing their last sentence to sort of dribble into nothingness. I attended a talk at the London Book Fair 2018 in which I missed every single point that one of the speakers made because every time she reached the end of a sentence she just mumbled. What's the point of doing that?
Remember that teachers are sometimes allowed out
Some speakers seem to overlook the fact that a few members of the audience might be teachers. This ought to influence them in at least three ways.
First, please don't say that in order to combat problem X, schools should be doing more. As I wrote in my article Fake news and FLOSR, schools are held responsible for everything from teenage pregnancy to obesity. Apart from the fact that the school day is crammed enough as it is, calls to make schools responsible for your particular bugbear are heard by teachers as yet another criticism.
Secondly, if a teacher asks how she can introduce her kids to your sort of work, have a sensible answer ready. Saying "I don't know" means you haven't done your homework, while recommending some ridiculously expensive programme shows how out of touch with reality you are. It really isn't a good look.
Thirdly, don't ask "Do we really need schools?". The only speakers I've heard ask this question are those who have had a great upbringing, had a good education, and didn't go hungry. For some kids, school is where they get a square meal once or twice a day, and where they learn to socialise. Getting to where you are and then wondering if schools are necessary smacks of wishing to kick the ladder away to prevent the lower orders reaching your lofty heights.

I enjoy a good keynote, especially if it “delivers”. To my mind, a keynote should be informative, inspirational and entertaining. All too often, however, keynotes by so-called “visionary” speakers leave me feeling both uninspired and uninformed. I am left with having been entertained, which is all very well, but unless it’s an after-dinner speech I’m also left feeling cheated. So these days, where there is a choice between attending a celebrity speaker’s talk or that of an “ordinary” teacher who is doing great stuff in his or her classroom, I will almost always choose the latter. In fact, I have developed a kind of rubric that I follow when deciding whether or not to attend a celebrity presentation. It consists of a number of questions, which I’ve written up below. Feel free to use them if you think they are useful. Some of these questions cannot be answered until you have attended a talk given by the person in question. But you will know for next time.