Summarize this article:

You can make it easy for customers to leave reviews by creating a profile on relevant review sites.  The sites you use will depend on the industry you are in. However, you can begin by searching for reviews of your competitors and noting the review sites they appear on. Popular review sites include Angie’s List, Yahoo Local, Google Local, LinkedIn, Yelp, and CitySearch. Some websites will gather your reviews. For example, Reevoo or BazaarVoice will host reviews. These services make getting reviews easy, especially if you work in an industry which isn’t reviewed frequently on Yelp or other established sites. Put the information on the back so that it is easy for customers to find. You can write, “Send feedback to” and then include a list of links.

Summary:
Find relevant review sites. Choose a review service. Include your profile on your business cards.