The best way to stop outside noise in your room is to use a sound booth or add acoustic foam and acoustic panels on walls. You may also rearrange the furniture, carpets, and rugs to help reduce incoming noise. Depending on where the noise comes from, another option is to hang blankets over sound entry points.  Before getting started, try to determine the source of the sound, its entry points, and its reflection points. For example, if you live on a noisy street, you may use curtains and window treatments to mask unwanted sound.