Cutting to the chase here: a big splashy opening weekend is great, but having a long life after the opening weekend can be way more valuable to a films' success. How does that happen? Through satisfying the audience's expectation, which starts with the movie trailer. If the trailer represents the movie well, you have satisfied audiences, which leads to positive word of mouth and a positive Cinemascore. For writers, that starts with your logline - make sure that's top notch and that your screenplay represents your logline (and vice versa) well. At the end of the day, a logline, a movie poster, a movie trailer.... they're all about pitching your project to an audience.