Friendly Referrer Spamming
Most webmasters now use some kind of statcounter or analytics package on their websites to track visitors and general hits.
This can be used to your advantage when link building by using a watered down and more friendly version of referrer spamming.
Basically you research the keywords you are targeting, analyse the top sites, create a list of sites you are not in direct competition with, assess which sites have links pages (or look as though they provide information about other sites) and create links to them from your own site.
Then over the next couple of months you click on these links a number of times a day (preferably from different machines on different ISP’s) not too often, but just enough so as to attract a little attention when the webmaster studies his stats.
After another couple of months you email the webmasters, usng your URL in the title of the email. Now because they have probably seen your site linking to them in their stats (and probably checked your site out to) There is a far greater chance that they wil read your email and respond to it.
This is a particularly good technique to use on low traffic niche markets, as not only does it help with your linkbuilding it can also help you develop relationships with the webmasters of similar sites to yourself, which can benefit all concerned.