Protect the physical security of of your computers, devices and sensitve documents. (For example do not leave them by the coat hangers at the restaurant door.)
Physical security is also about protection of your data even if the device is broken.
If you have backups, you can get the data back. If your device is encrypted, you can be sure that it's data cannot be misused.
Physical security of your devices
For desktop computers, the physical security of its location is important. Make sure your office is locked when unattended. Make sure the windows are secure enough to prevent theft. For mobile computers and smartphones and tablet devices, make sure you keep them safe when in cafes or when in transit. Such devices are easily and often stolen, or easily left behind and lost.
Encryption protects you if you lose your device
If you do lose a device, or it is stolen the two most important preparations you need to have made are: that it is backed up regularly, or at least of all the important data on it that you had encrypted it, so whatever happens you are sure no-one can access its data For mobile devices that support remote-wipe, we also recommend that you work out how to do a remote-wipe (ideally you should have tried this out as a kind of "fire drill"), and that you remote wipe it as soon as you are able.
Backups Having a regular backup regime is important if (unfortunately) your computer is broken, stolen or lost.