Avoid setting up your entertainment unit on the shared wall of your condo. If you watch TV with the volume high, or listen to loud music with considerable frequency, your neighbor may hear or feel the speakers' vibrations through the wall. Though it's not always possible to place your unit elsewhere, look for an alternative location.
Keep the volume on your TV and stereo to moderate levels if you have to situate the entertainment unit on the shared wall. In a condo, it's common to occasionally hear your neighbor, but if the noise is continuous and late at night, you may have a problem with the person on the other side of the wall.
Wait until the daytime to hang pictures and other elements on the shared wall. Though you may be anxious to get your condo set up as quickly as possible, hammering nails into the shared wall late at night won't make you any friends. If possible, wait to complete the work until the middle of the day, when the neighbor may be out at work or at least not sleeping.
Resist banging on the shared wall if you hear your neighbor making loud noises. Though the loud noises are inconsiderate, banging against the wall will raise his ire. Instead, ask your neighbor politely to keep the volume down the next time you see him in his driveway, or slide a polite written request under his door.