"How to Pick the Right Tone, Shots and Music for trailers"

At the first stage of editing, it is important to view the clips as an audience. Consider what is going to make people excited, interested and trying to find unique moments of the story.
It can be useful to find film trailers that you enjoy, from your chosen genre, and brainstorm what it is that attracts you to it and attempt to apply it to your clips.

It is important that the trailer has a definite narrative, if the audience can't understand what is happening they won't want to watch it, it will seem confused and unconnected. Similarly, if the trailer shows the climax of the film it will eliminate the audiences need to see the film.
More modern trailers have a conventional five part structure that they follow:

1. Start with a scene from the start of the film
2. Define the setting
3. Character Introduction
4. Plot Introduced
5. Hook

Start with a scene from the start of the film
It establishes the tone for the film and is used to grab the audiences attention and keep them watching.

Define the setting
There are two ways of defining the setting; one with the use of post-editing titles and another with the characters defining who they are.

Character Introduction
This is the stage where the audience meet the character before they have undergone their transformation. They are often introduced in a series of sound bites.

Plot introduced 
It explains the plot of the film, without revealing the plot twists and the climax of the film. It builds their excitement and feeling of tension.

Hook
The goal of the trailer to make the audience want more, it can be done in many through one-liners and dramatic montages. It depends on what the producers want their audience to remember.

(Information gathered from https://www.premiumbeat.com/blog/how-to-pick-the-right-tone-shots-and-music-for-trailers/)