As for me it's better to make a site telling about your affiliate program, and optimize it for SEO, anybody who are looking for an affiliate program will find your site
You can always go easyway with CJ, Clickbank or azoogle. www.cj.com www.clickbank.com www.azoogleads.com Good luck
There are two ways: - if you have already site and want to promote products associated with your site - you select the one with best products for your site. - if you want to promote one affiliate you select the one which works good and fair, with good commissions, fast payments, good tools...
Contact them personally... via emails or phones... It's slow but it's the most effective ways. I'm sure you don't need me to teach you how to find their emails or phone numbers, but in case you need, here are the two ways: 1) Signup for their newsletter or mailing list. 2) Buy their products Either way, you'll not only get their contacts but also a guaranteed response since you're in their list. Here's one additional tip, if they don't response, then you can consider giving them up because you wouldn't want to risk your reputation by asking someone who can't even handle their own list to help you promote your products.