It honestly just starts with watching a ton of trailers. Pick up common methods, like placing line delivery before or after the music hits a certain beat. Figuring out the pacing of the kind of trailer you want to do. Pick a theme and stick with it, like showing Nate’s obligation to help Sam and how that affects Elena. I personally like to take notes of where special action bits and lines are so I can use them later. Editing takes a ton of patience. This is not the first Uncharted trailer I’ve tried to do, largely because there are already some pretty fantastic ones out there, and at a certain point I just wanted to stop. Stick with it, do the work, and eventually you’ll finish something you like ✌️