Unless you had an app on it that could track it, there really isn't any way for you to track it.
You can try your service provider/carriers. Then 'might' be able to help, but that is just a 'maybe'. Also, even if they can't help find it, they can cut it's service.
And you should go into any accounts you accessed on the phone and change all your passwords. Otherwise the thief will have access to everything.