How do i find a hidden microphone?

You can do this by following the below two approaches:

1. Call any person and sweep the entire room with the phone on your ears. If you hear a disruption in signal, then probably that may be due to the spike in electromagnetic field and that area is bugged. Then do a physical search in the area.

2. If you are getting really paranoid, then purchase a RF indicator and run around the room with that. It will give you more precise location of the microphone if it is in fact planted in your room.