How to find the best pages to insert links?
Using the Google search engine is another way to evaluate the quality of a link for a given keyword.
It is legitimate for us to think that a web page ranked on first position on a given keyword is the most relevant page according to Google.
If you target this exact same keyword, getting a link from this page will certainly be beneficial. In this way, you just have to scroll down Google's ranking in order to get in descending order the pages where it will be most interesting to get a nice backlink.
Obviously, most of the time, your direct competitors will be the best ranked on your most strategic keywords, however, it is sometimes possible to find treasures.
In addition, if you observe the netlinking of your competitors with the right tools, you might detect websites from which to ask for links can be as relevant as for your competitors. Once again, there is no universal rule, common sense and knowledge of your field will be your best weapons.