Secured my idea

My trailer idea was initially going to be a male and a female character in a relationship when one disappears into a car wash. I was planning to have one male and one female when I was thinking about the limited amount of males that would play the part. During my planning I then came across the idea of having two female best friends where I could show there friendship with a number of different shots and props.
With this idea now secured, now I'll research more on the topic of trailers to get a clearer idea of how a trailer is set out, shots, sound effects and what most effectively attracts the audience.