Be very clear with your request for reciprocal linking. After you have thoroughly researched a potential site to ensure they are appropriate and actually do have links to other sites, consider the following:
Take care in crafting your reciprocal links letter. Make sure it's the best it can be before sending it out. Remember, you're asking for a favor (a mutually beneficial favor, but a favor nonetheless), so be polite and respectful in your letter. Otherwise, you'll get nowhere fast.
Create a "Link Exchange Letter," requesting a link exchange with your site, to each of the sites you have noted in your list. Make sure you've come up with at least 50 good quality content, non-competitive sites with a decent PageRank score of their own to email.
Example of a Link Exchange Letter from Eric Ward:
Hi <name>, my name is Hemant.
Regarding your SEO forum site at http://www.seooffice.com/
This month I'm helping the E2Solutions (SEO company) announce their new Web site about SEO community. The site is the companion site for their real-life SEO problems," which premiers this month (June).
Details about the site are below. Please feel free to feature or link to this new content in any way you feel appropriate.
By chance is your seo news section at http://www.seooffice.com/general/seo_topics.htm a good fit for it?
Also, if you have any questions or need anything feel free to contact me at hemant@domainname.com or (000) 111-2345.
I'm a real person, not a link request bot :) :)
Best wishes,
Hemant
on behalf of The SEO OFFICE
E2Solutions Site Announcement
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E2 Solutions
http://www.e2solutions.net/
(End of sample letter)
The above example is for a non-reciprocal link request, and it resulted in a link being obtained for my client. It could be changed easily to make it a reciprocal link request by adding one sentence that says where you gave them a link.