iPhone 5S was stolen

iPhone 5S was stolen over a night ago. Find My iPhone is installed but location services and net access are turned off. I have already turned on lost mode in Find My iPhone but it's still on 'pending'. Assuming that the soulless folks who did this are professionals I'm worried that they migh've already done something to negate all ways to retrieve my phone. I was just wondering if there are any more steps I could make in finding my phone? I still have the box and along with it the serial no. if that helps. Suggestions and tips would really be appreciated