Cyberspace
Keyboards
It is possible to eavesdrop the keys pressed using radio.
Also, watching the PC power lines.
Screens
Good 'ol Phreaking van Eck
Printers
Many color laser printers leave a small footprint in every page, with (usually) the date of impression and the serial number of the printer, among other data.
Digital cameras
Watch out for EXIF data. And pray for not getting "blessed" with unwanted steganography in your photos.
Meatspace
letters
You have to shred also the envelopes of the letters sensitive documents you receive
Locks
Most of the locks we use are so easy to pick that it isn't funny
Incidents, alerts
So, you've chosen to get a tinfoil hat
... and live inside a Faraday Cage
- You'll need TEMPEST
- You'll need plausible deniability
- You'll need anonymous Internet usage
- You'll need strong ciphers (GPG, SSH).
- You'll have to stop feeding all of your personal information to corporations. Quit GMail