For better page ranking in search engines such as google, inbound and outbound traffic are an important area. You can register with sites such as Linkmarket.net, Linkalizer.com, Linkexchange.com and exchange links between the sites to increase your page ranking. Please check out the about sites as well as their services so that you can develop an opinion as to which service you would like in the site.
The link exchange links can be placed in a separate page dedicated to the same, so that they do not hamper the design and content in the site. Another effective measure is the banner exchange schemes, but they will force you to sport banners of other sites in your web pages.