Locate websites that compliment the topicality of your site. For example, if you sell camping equipment, link to RV makers, camp site websites and other sites that run parallel to the same products you sell and are trying to reach the same demographic.
If you're selling hearing aids on-line, link to
health care plans
glasses sites
walkers, canes and adaptive devices
cruise ships (seniors cruise a lot; they also buy hearing aids)
The key is this - if the link furthers the search of your site visitor (even though you don't get the sale) it's a good link.
Over time, as you collect related links you'll discover that some rank higher or lower but you will have a lot more links.
Good luck,
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