With sryeager being an exception, in general here are steps I find helpful.
1. Breaker box should be updated to move your room away from air conditioners, blowers, and other high draw breakers
2. Add a whole house surge protector
3. Put your equipment on an isolation transformer https://www.amazon.com/gp/product/B00008YMZO/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
4. Use shielded power cables https://www.mouser.com/Wire-Cable/Cable-Assemblies/AC-Power-Cords/_/N-bkrhnZ1yzvvqx?P=1z0t1rp
5. Stay away from Blue tooth and unplug wall warts. Both generate high frequency noise which most linear power supplies are not designed to filter
6. If your equipment has rca and earth ground connected each component going to earth ground creates a ground loop
1. Breaker box should be updated to move your room away from air conditioners, blowers, and other high draw breakers
2. Add a whole house surge protector
3. Put your equipment on an isolation transformer https://www.amazon.com/gp/product/B00008YMZO/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
4. Use shielded power cables https://www.mouser.com/Wire-Cable/Cable-Assemblies/AC-Power-Cords/_/N-bkrhnZ1yzvvqx?P=1z0t1rp
5. Stay away from Blue tooth and unplug wall warts. Both generate high frequency noise which most linear power supplies are not designed to filter
6. If your equipment has rca and earth ground connected each component going to earth ground creates a ground loop