The first thing you can do is fill out the form on the website of the program "Wait for me". At the moment it's the only gear not only in our country but in the world, absolutely free, existing only by volunteers and philanthropists, searches for lost people. By the way, you can check on this site, not looking for anyone of you – perhaps the man also longs to meet with you. Write all of the information that you have about the person. Who is he to you, where you met, how the man looked and, of course, the city of residence. If you have a picture of who you're looking for - be sure to attach it to the application. Maybe you can help.
Continue to actively use the Internet. Create threads on the city forums, ask the locals to help you. If you have a photo of the person, then attach it – it's possible that the person who learns something. Even in the cities almost all the inhabitants are familiar if not personally, then through one or two people, so it is likely that photographs of your person identified.
If the photos are not, still do not despair. Ask for help in a social network. There was a case when a young man, creating in network "Vkontakte" group, managed to find the girl he once accidentally caught a glimpse of at the airport. You can use similar experience.
Social networks can be used in another way. Set the search all the options – city, approximate age, and gender. Of course, if the city is large, you will have to browse a huge number of applications, but there is a possibility that you will stumble exactly on the right.
Post ads in local Newspapers. It may not be a quick and effective way, but it is quite possible that such a newspaper falls into the hands of the person you are looking for.
Post ads on the streets. It is possible that to go to this town is too costly or impossible for any other reasons. You may call any ad Agency in the city and to order announcement containing all information known about the person. Of course, this is all for a fee, but that will not do in order to find the right person.