If you’re developing video courses, here is a quick summary of 12 principles developed by Richard E. Mayer, which you may want to familiarize yourself with for the best learning outcome:

1. Multimedia – People learn better from words and pictures than from words alone

2. Coherence – People learn better when extraneous information is excluded

3. Signaling – People learn better when cues are added that highlight the key information and its organization

4. Spatial and temporal contiguity – People learn better when words and pictures are physically and temporally integrated

5. Pre-training – People learn better when provided with pre-training in names and characteristics of key concepts

6. Segmenting – People learn better when information is presented piecemeal rather than all-at-once.

7. Modality – People learn better from graphics and narration than from graphics and printed text

8. Personalization – People learn better when words are presented in conversational rather than formal style

9. Voice – People learn better with a standard-accented voice

10.  Embodiment – People learn better when on-screen agents display human-like gestures and movements

11. Animation – People do not necessarily learn better from an animation than from static diagrams

12.  Image  – People do not necessarily learn better by having the image of an instructor on the screen

Also, check out this great lecture by Mayer, explaining his principles.

https://hwpi.harvard.edu/hilt/blog/principles-multimedia-learning-richard-e-mayer