Time: Think about the length - it is said that people can keep their attention on video (audio) for about 20 minutes. This does not mean that the lesson cannot be longer, but try to include a "switch" or activation method after 20 minutes. The total length of the lecture should not exceed too much over an hour. These can be small tasks, answers in chat, actions. But do not use "reflection", it is not in online activities a good way to attract attention.
Slide: Don't make too many text slides - students will read them and won't listen to you. You will lose their attention and the chance of "being" with them in your lecture.
Platforms: Don't be afraid to enrich the video with other platforms where you can collaborate and solve specific issues of the seminar.
Online Synchronous Meeting
Check the technique: At the beginning, check that everyone is able to communicate adequately. You can then start recording.
Informing participants: Please announce in advance that (if) recording is in progress.
Eye contact: Try to look at the camera as much as possible, not at the screen, notes, or keyboard. If you are watching a presentation, which is quite common, the student feels that you are reading the content.
Feedback: Work with a text chat - let students comment or ask questions. In general, the understanding of video is worse than understanding in the classroom, and your contact is also weaker. You can't see if students understand - chat is a good way to make such contact quickly and easily.