What makes a good trailer?

There are a few thing that I have found about what makes a good trailer. Like:

• Starts slow and ends fast, this means that it does not matter if you only have 2 minutes and 30 minutes to explain the film, the beginning should always be calm.
• The rise of music in some scenes, for example of explosions.
• Uses a narrator to read us what we can see on screen. This is a non-negotiable characteristic of 99% of the trailers.
•  If it is an action movie, shows the best scenes of special effects. If it's a comedy, compiles all the funny jokes. people should learn this trick, but most of the times they end by going to the cinema to leave the room exclaiming: "if the best was in the trailer".
• All actors may shout. The voice of the actors can only appear in two forms inside a trailer. If they are in the screen we might see them shouting : run, now, be careful, more wood, etc, are some examples of perfect valid exclamations. If the characters does not appear in the screen they might use any monologue in which the guionist have been making a lot of effort and they will match the images shown creating a poetic composition.