What makes a good film trailer?

things that make a good film trailer are:

release date:
most film trailers show the release date.

ambient sounds:
A lot of action films use ambient sounds for more effect.

diegetic sound:
most horror films use diegetic sounds like creaking doors and footsteps.

cross cutting.
cross cutting is used in a lot of films and film genres to make the viewers have to think more.

good camera angles:
different camera angles are used for different reasons.
low angle
high angle
pov
voice over