There are a few things you can do to help soundproof your door. One is to put a blanket under the door. This will help to block out some of the noise. Another thing you can do is to use weatherstripping around the door. This will help to seal off any gaps that might be letting noise in. Finally, you can use a door sweep on the bottom of the door. This will help to block out any drafts and keep noise from coming in through the cracks.