Find through search engines
There are a number of search engines on the internet like Google, Yahoo and MSN, which can help you find a person's e-mail address. However, you should know the exact spellings of the person’s first and last name.
If you are not able to find the email address of a person through his name, you can search by typing his name along with the name of his city or his physical address. If the person has a popular business, you can also search his name with that connection.
Social networking sites
Since the previous decade, online social networking sites like Facebook and Twitter have become extremely popular, allowing us to communicate with our friends, colleagues, class fellows and family, without having to leave the comfort of our homes. There are millions who use these social networking sites and it is not very hard to find the e-mail address of an active person. However, some people actively choose not to disclose their contact details.
Many of us make profiles on Linkedin for our business connections. Search on the site and see if you can find the person you are looking for and whether he/she has shared contact details.
Search your previous emails
If you have lost or forgotten the email address of a person, you should always go through your old emails or sent items. You may find any old email from that person in your deleted or junk items as well.