Bedtime is a critical time in any family with small kids. Here are a couple of ways to make your kid's bedroom a place where the transition is a little easier.
Make sure the bedroom is dark - hang curtains or blinds that can block out sunlight
Try to decrease noise both from inside and outside the room- heavy, lined curtains are good for this, and keeping a quiet fan on (or any other background noise generator), also helps.
If the noise from inside the house coming through the bedroom door is a recurring problem, try adding rubber or foam weather-stripping to the door, and installing a door sweep to reduce sound transmission