You don't have to help people get from A-Z. Quite often they don't even know where to start so going from A-D is enough. Know your audience in advance though. Remember to pause and speak slower. It gives the impression you are really considering what you are about to say next and allows you a break. Don't drink alcohol before the talk (unless you need a shot to calm your nerves) and do have a bottle of water availabl…
Great insight, and I've found that to be true. Most of the time, they selected your talk based on their interest in the contents (and less so on your delivery), and so they want to learn a thing or two. They will be graceful towards your presentation (style, delivery, slides) if at the end they got what they came for: you sharing data, knowledge, insights or wisdom. You don't want that too difficult for them, so you should work hard on improving your presentation delivery, but sharing knowledge is appreciated over sharing jokes or just well-designed slides.