Start by typing your friend's name into a search engine along with their address. Oftentimes, the search results can bring about more contact details if they are rather open about their phone numbers. Many websites, like 123People, offer a lot of contact information about individuals.
Many people use their mobile phone numbers as their primary source of contact, particularly if they are working professionals - hence, search engines should be the first place to look when you're trying to find a phone number. If this fails, however, then you still have options.
You could always talk with mutual friends, too. They may be able to help you with the phone number. Chances are your mutual friends will have the number, but if not, then you could maybe contact some groups or classes that you know your friend is involved with. They must have the contact information for the individual so this is probably your best bet. Do make sure that the person you're trying to contact wouldn't mind you getting the number before you go to such extremes. As long as they wouldn't mind you getting hold of the number then there should be no reason why you can't get in touch with any of their groups.
If you use Facebook or any other social networks, then that could be another source of information. Not only can you send a message to the individual asking for their phone number, but you can also look at the information on their profile page that could contain other contact details, like their phone number. If you have a message for the individual then there's nothing stopping you from sending them the message by Facebook.
Ultimately, you have many ways to get in touch with the person using the Internet - but if you still can't find them, then why not use a phone directory book?
Many people use their mobile phone numbers as their primary source of contact, particularly if they are working professionals - hence, search engines should be the first place to look when you're trying to find a phone number. If this fails, however, then you still have options.
You could always talk with mutual friends, too. They may be able to help you with the phone number. Chances are your mutual friends will have the number, but if not, then you could maybe contact some groups or classes that you know your friend is involved with. They must have the contact information for the individual so this is probably your best bet. Do make sure that the person you're trying to contact wouldn't mind you getting the number before you go to such extremes. As long as they wouldn't mind you getting hold of the number then there should be no reason why you can't get in touch with any of their groups.
If you use Facebook or any other social networks, then that could be another source of information. Not only can you send a message to the individual asking for their phone number, but you can also look at the information on their profile page that could contain other contact details, like their phone number. If you have a message for the individual then there's nothing stopping you from sending them the message by Facebook.
Ultimately, you have many ways to get in touch with the person using the Internet - but if you still can't find them, then why not use a phone directory book?