what makes a good film trailer

a good film trailer needs the name of the actors clips of the film e.g: best clips most exciting clips .

Most of th film trailers have a voice over which will tell you what is happening in the scenes.

Most people use special effects to make i look more lively or scary like in the Rec 2 trailer.

This uses effects on when the infected attacks the SWAT team. It makes the clip rewind and then play a couple of times. And it has a scary ambiance to try ans scare the viewers.