Best practice in using reciprocal links to boost search engine rankings.
Wikipedia defines a reciprocal links as:
a mutual link between two objects, commonly between two websites, to ensure mutual traffic.
Best practice
The fundamental starting point for reciprocal link is having good quality content that another site will be happy to link back to. Once the content is place, sites can be identified a potential sources for reciprocal links. The key point here is that quality is more important than quality. The ultimate aim of a reciprocal link should be to drive traffic to both sites, therefore a link should add value to the users of your site by providing quality information and vice versa. With this in mind look for sites which are authoritative and rank highly for desired keywords. Conversely, avoid sites with poor linking strategies such as lists of irrelevant links.
Be aware that search engines are able to understand links in context, therefore a link should form a natural part of the page and add obvious value for the end user. For example, a blog comment which states that "this topic is further explored at www.anotherurl.com/another-page", is of greater value than a link in discussion forum signature which may have little or no relevance to the points discussed.
Finally, it is important to ensure consistency in back links. Search engines value consistency is linking text and urls. When discussing reciprocal links with another webmaster always provide an example of linking text or image and the required URL.
Link Popularity within the Site's Internal Link Structure
Make sure you are using internal links to the most important pages on your site. As with external reciprocal links, don't just rely on the links that appear in your navigation - use links within the body of the content to target pages and make sure you use good link (anchor) text and alt text.