Consider buying a membership to Klout and look for blogs/influencers that get a high score in your industry. From there, reach out to them about a possible affiliate deal.

Human emails are the best way. Try to keep it short and say what you do, why you like their blog and how you would love to start a program with them to promote your website.

The largest blogs will want to have a better deal than just put your name up, you will have to think of a campaign or something unique for them to promote. But at that point, you are getting high relevance shares.