Noise is a constant and nagging problem in many buildings and houses because of thin walls and badly insulated floors and ceilings. Some solutions include:
Walls: Hang sound-absorbing materials such as quilts, decorative rugs or blankets. Carpeted walls provide excellent sound-proofing. Some brands of carpet can be attached to the wall with adhesive. Or, a carpet can be attached inside of a picture frame that can be attached to the wall. Either way it will be help immensely with noise reductions.
Ceilings: Acoustical tile can be applied directly to the ceiling with adhesive. A dropped ceiling of acoustical tile with about six inches of insulation between the new and existing ceiling is a good option.
Floors: A thick plush carpet that is laid over a dense sponge-rubber padding works great. The padding must be dense, at least 3/8″ thick. The more the better.
From: Bottom Line: The Big Black Book