I always like teaser trailers because they don’t give too much away, you know? They give just a flavor of what the thing is.
A book trailer can be a handy little advertising tool.
It should be short, stimulating, and give just enough away to intrigue a reader.
There are full-blown movie-type book trailers which cost from $5000 on up. I don’t make those.
Mine utilize slides with music in the background.
I’ve seen some with authors talking about their book; for me, those draw attention to the creator of the story rather than to the story itself.
I keep trailers very short (under 30 seconds) and very focused.
If you’re interested, they are also very inexpensive.
I also do a premium trailer that lasts around three minutes and I compose the music. That costs more, but you can see one result here.
You can post it on YouTube, Facebook and other places.
See an example below.