don't just pick all the random crap people want you to pick just because they built it.
people want to see interesting things, not just some small build laying around. the trailer should show what you can expect from actually playing, not just a magic carpet's view of a build.
fights, minigames, deathruns, racing, shooting, helicopters, explosions, big things, variety. that's what goes in a trailer.
little cars or houses or lakes shouldn't make it into a trailer unless there are people walking around in them.
good: footage of a house, with people walking around or doing stuff inside, windows open so you can see.
bad: circling around a lifeless house.
good: people racing around a racetracks with some behind the wheel footage and cinematic shots
bad: sky view of a racetrack build without any people on it
good: people camping in the woods
bad: just the woods.
that shouldn't go for everything though. mythology build fits well without people, because it shows the true scale of something huge and cool. it's a full scale awesome build, not just a house or a lake
you should take some of the builds you want to feature and set up stage times with the creator and actors or something, or film various populated servers