I usually look for sites with the content related to what I have on my site, that also have a high google ranking. You've gotta figure that a site with a low rank won't flow you a lot of traffic.
By the same token you don't need a boat load of customers that aren't looking for what you offer on your site, wheres the use in that kind of traffic.
I try to update my site abut 3 or 4 times per month, to keep it fresh so people will return to look again, I think like to try to enhance my site with every link that I add to it and also bring coutomers that are looking for the product that I sell.
I look for links that will provide return visits to my site, a return visitor is an interested visitor, and one who will go out and tell people about your site and what it has to offer.
I'm constantly looking for quality links and more ways to find them.
http://muscle-car-resto.com Links are the one thing that you can control on your site.