What are the tips/rules/recommendations for creating promotional videos?

Question

Video

Hello toasters!
There is a task to develop videos about the service / product of the client.
Placement: on the website, on YouTube as a video, on YouTube as an advertisement, in social media posts, on Instagram, on blogs.
What advice and references would you give dear advisers?
1. Are there any guidelines for video length? How can they be crushed?
2. What is a good review?
3. What is a good script today?
4. Are there any rules for cutting shots?
5. What is the best way to make transitions?
6. What are the subtleties with the texts in the video?
7. Are subtitles required?
8. Are there any best practices for gestures and facial expressions?
9. Compositions? Color?
10. Sound recommendations?
11. Chips?
12. Top mistakes?
13. Equipment? Is it possible with an iPhone? Is it good on the knee?
14. And what to read about it? And to see? Listen?
I will be glad for any useful information :3

Answer 1

There will be no links
1. Are there any guidelines for video length? How can they be crushed?
If you are unknown - then small up to 20 minutes with a clear catchy start. Break it down logically.
2. What is a good review?
Watched video before the end, like and repost
3. What is a good scenario today?
Watched video to the end, like and repost
4. Are there any rules for cutting frames?
No
5. What is the best way to make transitions?
As you like, it is desirable to follow a single style
6. What are the subtleties with the texts in the video?
Be understandable to your audience
7. Do you need subtitles?
Doesn't matter
8. Are there any best practices for gestures and facial expressions?
It doesn't matter, act natural. There must be a certain style
9. Compositions? Color?
There must be a certain style
10. Sound recommendations?
It doesn't matter, the quality is as good as possible and that's it
11. Chips?
Yes. What - think for yourself
12. Top mistakes?
Do not learn from your past actions
13. Equipment? Is it possible with an iPhone? Is it good on the knee?
It's possible, it happens. Strive to be understandable to your audience
14. And what to read about it? And to see? Listen?
YouTube to help - tons of material.

Answer 2

0) everything is bullshit, except for bees.... yes, and bees...
1) the best way is to do similar / analogous to successful competitors