Do you know Latest Google Android version offers inbuilt support to track your mobile phone. This is done through Android Device Manager (ADM) which comes pre installed in most of the last Android Phones.
If you purchased the phone long back and didn't receive ADM app, you can install Android Device Manager from here:
https://play.google.com/store/apps/details?id=com.google.android.apps.adm
For tracing your lost mobile phone using this feature it is necessary that.
If you answered most of the above questions as yes, you can visit following URL and start tracking...
https://www.google.co.in/android/devicemanager
Login to this service with same Google ID and password with which you access Google Play Store from mobile.
ADM app on your mobile phone can give you precise location of your device in terms of Longitude and Latitude which can be seen on Google Maps and tracked.
This also shows you when was your phone last located and remained online on internet.
Using this online service you can send a ring to your phone. Once the ring is sent, it will play ring with full volume for 5 minutes. In case if you find the phone around you, you can stop the ring by pressing power button
You can also lock the phone to avoid stealing of your data.
Or you can erase all the data in case if you don't want that goes in anybody's hands. You can use this feature in case if you have taken manual backup of contacts, messages & photos or enabled automatic cloud backup, otherwise you'll loose all the data and there is no easy way to recover.