Problems I'm having whilst editing

Whilst editing, I have come across a few problems. One of these problems included, background noises, that are difficult to get rid of because I needed the audio for that clip. Another problem I have is that the camerawork on one of my scene is a bit shaky, making the trailer look non professional and not in great quality. Another problem I had was that, to stick to conventions of a movie trailer, I had to go in at around 40 seconds without showing the zombie, as this is what all the other horror movie trailers had done. The problem I had with that is that nearly every scene I had recorded included the zombie in it, so I had to record more footage, without the zombie in it that fitted in with the trailer.