There are many things to consider about a page from which you are requesting a link from. Of course, you want to take into account the relevance of the page to yours, the quality of the backlinks of that page, the PageRank, etc. Another very important factor is co-citation, which refers to the outgoing links on the page.
When a page links to your website, the other websites the page links to say a lot about your website in the eyes of the search engines. Google considers websites that are linked to from the same page to be “related”. Ideally, all other links on the page would be to other websites that are highly relevant to yours. If a page links to your website and also a bunch of spammy sites, it can actually hurt your rankings.
Let’s say for example you have a website that sells diamonds. It will help your rankings to get a link on a page that links to other diamond websites. Even better, if the page links to a page about diamonds on a .edu domain, Google will consider your website similar to the .edu which carries a great deal of trust.
To see what other websites Google considers to be related to yours, enter the query “related:yourdomain.com” into Google search. If the websites returned are not similar to yours, you need to work on your co-citation.
