I lost my iPhone 5, now how do I find it?

I was in my shop and I noticed my phone was not there. I don't know if it is locked or switched off but on Find my iPhone it shows that it is offline. I have ticked the box that says Notify when the iPhone turns online from my friend's phone. How can I find it?

Well at this point you'd have to wait & see when it does come back online. Should put it in Lost Mode for whenever it does.