How many times in a week do you receive an email requesting a link that clearly shows the person emailing has not even made the time to visit your site? Establishing reciprocal links with other sites means making an effort!
The real point is that you are trying to create a rapport and hopefully a lasting relationship with the site you have identified as being beneficial for a link, and therefore you need to remember that any email request will be read by an individual who probably knows their website inside out.
Link building requires you to get personal, be friendly, and show that you have taken the time to consider your request to them carefully by looking around their site.
So, when requesting links from others, it is always helpful to point out where a link to your content would be most appropriate on their site, and suggest anchor text. This can only be done by a manual inspection of their site, and by looking at it from their point of view too ie where a link to a specific article of yours would benefit visitors to their site.
To find out more about link marketing, see tip #45 in our Search Engine Optimisation book.