One of the most popular myths about backlink building is that all backlinks must from external sites to increase link popularity and search engine ranking. However, internal backlinks can be created by simply adding new content to your blog and posting new articles which creates links that link back to your blog or website. These internal backlinks from blog posts are the best to start with if you have a new single blog or website blog because you don't have to rely on begging other websites or use other backlink tactics like reciprocal linking or blog commenting to get links from other sites.
In addition, once you have built these internal backlinks from articles on your blog and start receiving search engine traffic, readers of your blog will link to your blog from other sites if they find the articles on your blog useful which is how external backlinks are usually created and give your site more credibility in the eyes of the search engines.
In conclusion, if you are just starting out with your blog or website, focus building internal backlinks by creating articles on your blog that link back to your site, because not only does this create backlinks for your site, but it also gives your site content that the search engines can frequently come back and index when the crawlers revisit your site. Once you have done this, you can rely on the quality of your content to build external backlinks as people will link to your blog articles from other sites if they find it useful.