Noise driving you crazy? Family members, room-mates, neighbors making too much racket? Or are you the one who's creating the hubbub? Whatever the case may be, sound dampening your room may be the way to go. To get started though you have to understand how sound and noise works before you can defeat it. Sound waves travel through air and some materials can dampen these waves. Vibrations are another source that can create noise by traveling from one object to another and vice versa.
If money is not a problem then using manufactured sound dampening materials is the way to go. Made from polyether foam and vinyl these composites absorb sound. Others are made from recycled cotton fiber layered into tiles which decrease sound from the walls and ceilings and reduces sound wave vibrations. Some products are made of heavy, flexible vinyls that become part of the wall, ceiling and floor. They are then covered with normal sheet rock or paneling.
Remember that windows and doors will also contribute to a noisy room. Weather-stripping doors and windows can also alleviate sound waves from entering. You can also purchase peel-and-stick vinyl materials for the windows which are obviously easy to install.
The simplest and perhaps the easiest solution to dampen the noise are to use conventional methods like carpeting on the floor. Then use cardboard chicken egg trays that can be purchase online to cover all four walls and door. Once this is done you can hang thick drapes all along the inside room also covering the door. Make sure the drapes are long enough to hang from ceiling to floor. These simple steps will dampen the outside noise dramatically.
Based on what you want the end results to be there is a wide variety of options in sound dampening a room. Are you trying to get a good night's sleep? If so, and you want to save a whole bunch of money, simply purchasing an eye mask, ear plugs and using a white noise machine will do the trick. If you're looking to create a recording studio then methods and materials need to change drastically. Remember that "sound-proofing" a room isn't practical because it eliminates air-waves, air which you need to breath.