Getting quality links to your site from related web resources can be very difficult. It is a time consuming process and requires careful research. There are two ways to build your link popularity;
1 Make your site attractive to webmasters or
2. go out and hunt them down your self.

Getting webmasters to come to you:

Having lots of useful content on your web site such as informative articles, online tools, studies, etc will make another webmasters what to link to your web site knowing that you will not only help their site's traffic and link popularity, but adding content to their own web site.

Sometimes you may even get webmasters that like your site so much that they will link to your homepage or to certain web pages that they think their visitors will find useful because this adds to the usefulness of their own site by providing useful links.

Keep it clean by avoiding tricks (Blocking access via robots.txt to robots, linking out with JavaScript, etc.) meant to keep your site from transferring Page Rank to other webmaster's web sites and link to your links page on every page of your site.

Sometimes you will get requests for link exchanges with web sites that are not related to your site's topic, these sites should be ignored and you should focus on only related web sites.

Hunting link partners down your self:

Type your keyword phrases into a search engine and wait for the results. The web sites you see on the first few web pages of the search engine results should be your main targets and should be looked at. Visit their site to see if you can find the site owners name and email them asking to exchange links, remember to email them at the right email address, don't email the email address that's for support.