Recently, I had my phone stolen and was really worried about my personal data that was stored on it so here I have made a list of what to do to protect your data if you ever get into this situation.
Register your IMEI [International Mobile Equipment Identity] number. This is the number used by the Police when trying to recover a stolen phone, without this number, the are virtually no way you can protect your data. Network providers also use this IMEI number to block a stolen phone, so that nobody else can use it. Your IMEI is usually found under the battery of your phone;you can get it on-screen by dialing *#06# .Register you phone at www.immobilise, a site set up by the police.
Create a Password. This is your first line of defence against someone stealing your phone.
Remotely Wipe All Data. If you have lost your phone, you can clear the data before anybody else get to it. Android users can use Google Sync along with Google Apps Device Policy to clear data remotely. iPhone users can use Find My iPhone for this, and Blackberry and Windows Phone users can try out Lookout.
Get Antivirus Protection. Especially Android users, where virus attacks are much easier to perform than on another device.
Download a Phone Finder App. Most smartphones now has GPS that will make tracking easy and fast, so that you can see exactly where your phone is at any given moment. For Windows Phone users there is a free app called My Phone for Windows Mobile, which is made by Microsoft. For iPhone there is the Find My iPhone, and for Android, I would recommend a free app which is called Theft Aware.