Change all of your passwords: This is the very first thing you should do after losing any device containing valuable data. Start with your email password--once thieves have access to your email, they can easily break into all of your other online accounts by resetting your various website passwords.
While you're at it, now might be a good time to revisit your approach to passwords, making them stronger--and easier to remember in the process. Want help? See PCWorld's tips for .
File a police report: Once you have changed your account passwords, file a police report for your missing tech. Be sure to mention any identifying features (say, engravings or other customizations), as they will help other people recognize your device. You might also want to alert any local pawnshops in case someone tries to sell it for a quick buck, though this step may be time-consuming.
Track your gadget: If you have installed recovery software on your gear, activate it and use it to gauge your device's location. For most tracking products, this means logging on at the service's website and tracking your wayward gadget via the control panel. At this point, it's entirely up to you whether to pursue your device or just give it up for lost and wipe it remotely.
On iOS, a remote wipe will erase all content on the device. Wiping an Android phone or tablet will clear most of the user data, but SD Cards and other pieces of external media will remain untouched; keep that in mind if you store a lot of critical information on your SD Card.