"Look for anything in your surroundings that appears disturbed, out of place or odd."

"Surveillance can be done by more than clunky nanny cams. It can be conducted with wireless microdevices, some as small as a postage stamp, that can be stashed in hard-to-spot places like inside clocks, light fixtures and air vents. Be wary of anything with an inexplicable hole in it, like a hole drilled into a hair-dryer mount in a hotel bathroom. And scrutinize any wires trailing out of something that’s not obviously electronic, like a desk, a bookcase or a plant.... [Turn] off the lights and [use] a flashlight to scan a room to see if the lens of a camera shines back at you. If you don’t have a flashlight, look around using the front-facing camera on your smartphone (the side you use for video chats), which may allow you to see the otherwise invisible infrared light that spy cameras emit.... [V]oyeurs may use spy gear that has its own hot spot for live streaming. So... check for other Wi-Fi networks in the vicinity that have a strong signal... 'For every one camera that’s been found, there have probably been a hundred cameras that haven’t been found'...."

From "A Paranoid Guide to Fighting the ‘Bugging Epidemic’/With surveillance gear cheaper and easier to use, security experts say checking your environment for cameras and microphones is not a crazy idea" (NYT, with a nice illustration (by Ariel Davis)).

If you're really paranoid, you can never get naked, use the toilet, or have sex anywhere other than in your own home. And worry about whether somebody has bugged your house. You won't be safe from spying until you die, and maybe not even then. I bet spycams planted by crazy voyeurs are inside some buried coffins.