I am expected to teach a large (80-100 students) graduate level class in AI this spring. The class is offered exclusively online, and students from various backgrounds are expected to join. It is not possible to meet face to face, as they are spread all around the world. Office hours are also virtual. I am very interested in learning about effective ways to manage and motivate this class.
From my own (limited) experience with teaching online and offline, I found that the number of people that are really engaging with you, showing initiative and asking questions is mostly a small fraction of the whole group and when moving to online teaching, that fraction decreases even further.
But what seems to work in terms of engaging the students and adding interactive elements is incorporating surveys or quizzes into the teaching structure, the latter could even be used competetively (who solves it the fastest?), adding a gamification element. There are great online tools to use for that prpose, e.g. this or this.
Another issue with online teaching is that people often aren't as concentrated and tend to do other things on the side or even stop listening altogehter. I recently participated in an online conference as a speaker. That conference was organized by a university and students could get credit for attending the whole conference. To get the credits, they had to take a short survey at the end of each block that asked several questions regarding the content of the lectures of that block, ensuring (to some extent, as a system like that doesn't prevent cheating) that the students actually listened to what was said. Maybe a similar solution can also be introduced when teaching a class.
Some things will be very similar to in-person. Don't speak in a monotone and such-like advice. Speak neither very fast nor very slow, but find that "sweet spot." And so on. All the little things that make speaking to a group more than just reading off your slides. Make sure they have time to write down stuff if they need to.
Pick your software and learn the quirks. If you wind up spending 20 minutes of a 1 hour class messing with the software it will be annoying. Make sure you understand how to make your camera and microphone work and other mundane stuff. Make sure you are reasonably well lit so you can be seen, if you are using a camera. Make sure in advance that your microphone works. If you are recording make sure you understand how to start and stop that. And other such "mechanical" stuff.
Usually you want to mute everybody else's microphone during your presentation.
With 100 people it might be a problem to have questions during. Or maybe not. Some software lets a text chat go on during the presentation. Maybe they can ask questions and answer each other. Keep an eye for it becoming disruptive.
Make sure you know how to distribute extra material, files and such. Email to the group? Stick it in the chat? Make sure you know what works so it does not delay the class.
If you are going to show computer screens of info, or show them how to do stuff on screen, make sure you know how to show your screen, and how to get back to your camera.
Make sure your location is free from interruptions. If the dog and the cat and the toddler wander through, each getting their 15 minutes of fame, it uses up time that presumably your students paid for.
After that it's how to fit stuff into a computer screen so that it is interesting, informative, and covers the class material.
My personal bias is avoid PowerPoint and anything that looks like it, but that's just me. Every PPT presentation winds up looking like every other one, rows and rows of bullet points.
Make use of drawings, tables, graphs, etc., as makes sense.
With a group of 100 you might need an assistant. You might not see a question while you are busy explaining technical details. Your helper can keep an eye on the chat and whatever your software uses to indicate a raised hand. They can nudge you when there is a good time to stop and answer questions.