I think a great video can be made by simply talking into the camera or being interviewed by someone. Keep in mind that a book trailer and a crowdfunding promo video are two different things; the first can be used for the second, but the structure and content will be different.
The best advice I can give for a crowdfunding video is that the video should give people a reason to find enough confidence in you AND enough interest in your book to convince them to pre-order.
So, to build confidence in you:
Seem relatable to your target audience. You want to reach nerds, be nerdy, etc.
If you want them to think your book is funny, be funny in your video.
Don’t waste their time; short videos are essential.
Be neither arrogant nor self-deprecating. Don’t talk about what you haven’t accomplished or ways you’ve failed or doubts you have. Focus on your goals and give people the impression that you have every intention of reaching them.
Don’t talk about what you’ll do if your campaign fails. Stay in the mindset that you’ll succeed.
To build confidence in your book:
Tell them why your book is unique and/or exactly what they’re looking for.
Be interested in your own work.
Make comparisons to well-known properties to help them understand what they’re getting into.
No doubts or wishy-washiness about the quality of your book. If you’re not totally confident in your book, why should anyone else give it a chance?
Figure out a really good hook and use it!
And beyond all that, I recommend you watch a ton of crowdfunding videos first. Figure out what you like, what bores you after 10 seconds, and what convinces you to throw your hard-earned cash at a stranger. It will really help.
You can also do a book trailer, which isn’t really about you, the author, at all. Kyle’s approach of reading a chapter is also a great angle to take.
Overall, lots of books have reached funding without having a promo video; I think they help, but only if they’re actually good. Good luck!