Exchange Links

Link exchange is the process of exchanging links with other related websites with the objective of getting related traffic and pagerank.

Steps

Build a site worth linking to. This is the most important step. If your site is good, you will get links without asking for them. If not, only other low-quality sites will link to you.
Do a search in Google and try to locate as many related sites as possible.
Link to their site first. (Because their site, like yours if you followed step one, is worth linking to even if you don't get a return link.)
Send an email to the site owners/webmasters requesting them for a link exchange deal. Include your URL and a brief explanation of your site, their URL that you want the link from, and a meaningful subject line.
Either incorporate their link into one of your content pages, or have a well organized, annotated link directory. Don't just bury their link among hundreds of others on a links page where nobody but a search engine will ever see it.

Make sure that the page on which your link is placed is linked from the homepage and has been indexed.
Go for sites that are horizontally and vertically related to your site.
Exchanging links is not necessary in order to have a top ranked website.
Exchange links with pages that have a page rank similar to yours.

Do not exchange links with link farms or websites specifically developed to aid the process of link exchange.
Don't threaten to remove links if you don't get a return link, or if you don't like the way the other webmaster presented your link. You might as well just tell him, "Your site sucks. The only reason I linked to it in the first place is because I thought I could get something in return."