look for relevant websites and search in their website to see if they have a link or partner page, then email them and customize your message, say something nice and specific about their website, auto exchange tools are a waste of time, they send junk, and will either end in the spam folder or be totally ignored by the webmaster.
Also remember that reciprocal links are not nearly as powerful as one way inbound links. Remember, to build good pagerank, you want more quality links coming in than you have going out.