Ok, so you have noisy neighbors, welcome to the club. The rap music at 2:00am, the constant bickering, fighting, and yelling, and the infamous 'wake startling' door slam on the other side of the wall can drive you nuts! If you have paper-thin walls you may have problems with quiet neighbors as well. You may be able to hear regular conversations in detail, a normal volumed television set, or the early riser's alarm clark in apartment 2b.
So what can you do? First, its always best to talk to your neighbor and let them know that their noise is effecting your lifestyle. This can solve the problem in some situations, but unfortunately not in all cases. There is also the solution of finding a new apartment, but as we all know this is both expensive and impractical and with your luck your new neighbor might be even louder (or an aspiring rockstar drummer).
Ok, so jokes aside, there are a couple of ways to help solve the noise issues and they all include making your shared wall a soundproof noise barrier.