How to prepare myself & smartphone/tablet in the event it goes missing or is stolen?
There are multiple things which can be done:


Device encryption (to assure all your data is stored encrypted)
Install anti-theft software (to track and, if necessary, remote-wipe a lost device)
Activate Google's Device Manager on your device (and make sure it works, as it not always does)


To photograph the "perpetrator", you might want to take a look at ☆ GotYa! Face trap !, which fires at failed logins (but requires a front-facing camera to do so):



One of the most well known anti-theft solutions is e.g. included with Lookout Security &amp; Antivirus, but the playstore offers a lot of alternatives to this.

For keeping a copy of your important data off-device, you might use some cloud synchronization service (or a similar thing to sync with your own machine(s) at home). When storing data in the cloud, you might prefer using encryption; Wuala is one possible solution which encrypts your data before it is transfered into the cloud.