Film trailers are a highly condensed, highly stylized version of the movie they’re promoting. The trailer is an art form, a way to present even the most flawed movies in an attractive light. Over time, studios have perfected the craft of trailers to the point where they’re able to market even a terrible movie with appeal.

Often, a trailer will feature a few key scenes from the film, and may also include some material that is not in the final movie. This is especially common in action films, where the trailer editor may cut together footage that isn’t necessarily part of the plot.

In addition, some trailers will contain a cast run, a list of the principal actors in the film, as well as director and producer credits. This is generally presented at the end of the trailer, and it is typically the same list that will appear on the film’s posters and print publicity materials.

Trailers are a crucial component of any video project. They’re often the first impression a viewer has of the project, and they play an important role in enticing viewers to watch the full version. But, when it comes to making a trailer for your short film or music video, it’s easy to fall into certain traps that can derail your whole effort. Here are seven of the most common trailer pitfalls, and some timeless best practices to keep in mind when creating your next trailer.

Ultimately, the most important thing to remember when creating a trailer is to tell a story. The most successful trailers use visuals and dialogue to build tension and excitement for the movie, and they create a sense of anticipation by showing only snippets of what’s to come in the film.

The trailer for Argo is a great example of this. It balances two different tones—thriller and Hollywood satire—by using both fast cutting and long shots. The last shot, in which a man sits in silence, is particularly powerful because it draws attention to the fact that the audience isn’t sure what will happen next.

Many film trailers also use “special shoot” footage, which is material shot specifically for the trailer that does not appear in the film itself. A famous example of this is Alfred Hitchcock’s trailer for Psycho, in which he gave viewers a tour of the Bates Motel and ended with a shower scene that showed Vera Miles giving a blood-curdling scream—all of which was shot after the film had been completed but before its theatrical release. These kinds of extra footage can add a lot of flair and interest to the trailer, and they’re often the source of much discussion on social media after the film’s release.