I think how my characters look and are represented is very important for my trailer as much as everything else. It's important I follow codes and conventions of my genre and also think about audience theory as I want the audience to empathize with my lead female protagonist follows the uses and gratifications theory.
I've looked at the dress of some characters in some films of my genre including: Raise Your Voice, Hannah Montana The Movie and A Cinderella Story.

All these characters are dressed very casually, and look relaxed. The look consists of T-shirts, jeans and trainers. I think these makes the audience interact when the characters easier as they aren't these make believe types of girls, they are normal, most likely the audience who would be watching the film. The audience will decode the ideas I have encoded into my text to help build character and personality.