Back in the day losing a telephone wasn't as big of deal as it is now. Phones are notably more expensive now, and hold much more sensitive data. It might be too late to know this, but it is actually vital that you lock your telephone with a password. This way any sensitive data on your phone is safe. Also, you need to have your phone's ESN, IMEI or MEID amount (usually found behind the battery or on the back of the iPhone near the FCC ID) in case you lose your phone.

Visit this website to know more about it : IMEITracker.org and Track IMEI India

Text and call your phone- Plead, offer a reward, it can't hurt at this stage. You may see your phone again after doing this, but do not count on it.

After texting and calling your phone call your cell phone carrier. Let them know which you have been lost by you cell phone or it has been stolen. You can ask them to suspend the services of the device, so that the chance of a thief racking up expensive fees on your phone is eliminated.

Use Safety Apps- With smart mobile phones there is an app for helping you come across your stolen phone. There are apps which will track your telephone with a GPS tracker. There are also apps which will wipe all the data that is stored on your phone or just lock the phone until you can get to it.

For more information visit : https://en.wikipedia.org/wiki/Mobile_phone_tracking

Retrace your steps. This is real with anything, and it is real with a phone. While there is a high chance that someone picked it up where you left it, you can find lucky and find it seated where it fell out of your purse. It can also help to check your local police station in case a Good Samaritan turned your mobile in.

Don't panic. While shedding your phone is a very frustrating experience, it is not the end of the planet. It will also be difficult to solve the problem if you are freaking out. So take a deep breath, think logically. The worst that can happen is that you will have to buy a brand-new cell phone.
If you are very active on your phone, you might want to consider backing up your phone. This will safe guard your apps, purchases and other valuable data. This actual way if you do have to buy a new phone, you won't have to start over completely with your new phone.