Trailer music relies on the contrast between extreme quiet and extreme loud (tension and release).
Massive, low brass-style stabs (popularized by Inception ) that add a sense of scale.
To make drums sound massive, "flam" your hits—slightly offset multiple drum samples so they hit at slightly different times, creating a larger-than-life doubling effect.
Watch these professional walkthroughs and tutorials to see how epic trailer music is composed and structured: How To Compose EPIC Trailer-Style Hits YouTube · Woodyard Music Let's Make an EPIC Cinematic Trailer Song | "Heartbeat" YouTube · Trev Barnes How To Create A Movie Trailer YouTube · Motion Array Tutorials Swagger Rock Trailer Music | Walkthrough YouTube · O'Connor Productions
Often, the tempo is slowed down, and the arrangement is stripped back to just a few eerie elements (like a "spooky piano" or a drone) for the first act.
Gradually layer in cinematic percussion (like "wide war toms") and orchestral brass to the original melody as you move toward the climax.
Creating a "trailer song"—whether you are composing an original piece or "trailerizing" an existing track—is an art form centered on building and maximum sonic impact . 1. The Three-Act Structure