Remove batteries (if they have them) and store with camera.
Store in heated room.
Wrap them in a clean, dry, lint-free cloth. Use a tube of bubble wrap to protect from other nearby objects.
Do not use sealed ziploc bags. Will promote moisture from condensation.
Do use gel paks. Regen based on manufacturer recommendation. Write date of last regen on sticker, place on gel pack.
Exercise all shutter speeds, film transport mechanism, self timer, etc. once every six months. Write date on string tag and attach to camera.
Use camera body caps and lens caps. Buy cheapo e-bay ones if you need to.
Wrap lens in sock and store in own case or a tube of bubble wrap. (Resist the urge to pop the bubbles.)
If you use the camera fairly regularly, send to a trusted repair person for a professional CLA once every 5 to 10 years (based on your use.) Heavy use will require more frequent service.
Wipe them down occasionally with clean, dry, lint-free cloth. Do not use armor all or other oils unless specifically recommended by the manufacturer in the user manual. Then use only what is recommended.

If you actually do all that they will outlast you, unless the electronics puke on you.