One thing that people neglect to pay enough attention to before they participate in a video call is the background. You want to find a spot without a lot of distractions or large objects hovering over your head. And if there are windows, make sure they are covered with blinds so you don't have a lot of backlight.
You want the viewer to focus on YOU, so make sure that what is behind you is neat and not too cluttered. I've noticed that a lot of people position themselves in front of a bookcase, which can communicate that are are well-read, but is the bookcase orderly? If there are books packed into every open spot or if there are too many trinkets, this can be distracting for the viewer or give the impression of disorder.
Once you have created an orderly background, position yourself so the viewer can see you from the shoulders up, and your head is centred in the screen, or slightly higher.