There are many reasons why your site should be optimized by link or backlink building. Backlink is a crucial part to get high ranking in search engine, but we also have to look at, where does the link come from. A good site will be able to provide a good backlink to our website which also affect the ranking in search engines and not even drown our site.
The more quality links to a site, the better for it appears on the search engine result. For example; you ask A to put a link on their site and link to your site. First, see how many link from A. We know that search engines rate more if the site linking to your site has relevant content.
Link building is one strategy to determine the optimal quality links to your site/ blog. You may find a few directories those are relevant to your site. Or you can also find similar sites and link to your site. With the relevant links from quality sites, then you will get much better than links from irrelevant sites.