How to find the location of my lost smartphone?

Log in to www.google.com/android/devicemanager.
If your device is linked to your Google account and you are logged in, the location of your device will be shown. You will be able to lock your phone or wipe all the data remotely. It depends on what you have set on your device.
You can find location history of your phone via Google maps.You will need to click on the GPS icon on the device manager website.

If you have installed Find my Phone on your phone, it can be used to find the location of your phone.

There are some of the android apps that allows you to track the phone if it gets lost. And such services have web app that helps you to track mobile inside the dashboard.

Few apps that allow you to do that are - Plan B, SeekDroi and Cerberus.

There are many free apps however paid apps gives you acurrate tracking features.

If you use Mi phones then you may find option that allows you to track the mobile. It shows the map and location of the phone by guessing through the network.

The accurate data is available to only mobile operators. They can track your mobile using IMEI number.

If you have lost your smartphone then read the details given below to know the two best ways to find it out.

1. You can track your smartphone online at "http://www.trackimei.com/".

2. File an FIR to your nearest police station for your lost smartphone and then police will help you to find or track your smartphone through Surveillance.

3. Surveillance is a police investigation of tracking any mobile phone. And only police has the authority for Surveillance, you can't do it own your own.

I hope you will find your smartphone soon. The best option I recommend you to go for is to file an FIR for your lost smartphone.

It depends on what you have enabled on your smartphone.
If it was linked with your google ID then login your google on another device and you can remotely access your device, even you can lock your device.
Another method, if you have installed some mobile tracking software on your device then also you can easily trace the location of your device.
You should make an FIR for your lost phone as one may misuse it to do some illegal purpose. Police will trace your device and by your EMEI number police will detect the person if he is using SIM card in the phone.

Go to: https://www.google.com/android/devicemanager

If your smartphone is not switched off then you can get the location of your device prompted by the Google. Moreover, you can remotely ring, lock or erase the data of your smartphone with the help of above service.