1. Trade links with other websites. Websites that are related are best, simply because the user is more likely to be interested in the related link. For example, if someone was looking around a web design site, they are more likely to be interested in a web hosting links than a sausage appreciation society website. However, any link is good (as long as it isn't with a subject you don't want to be affiliated with, i.e. adult websites). It also has the added advantage of increasing search engine rank.
Websites to help with this would be: www.gotlinks.com, which is an automated link exchange. www.linkmarket.net, which is semi automated link exchange. www.honestlinks.com, which helps you build a successful link page.