Website authority does not only depends upon the back links but also depends upon the quality back links. Whenever you built back links, always make sure that those back links should be related to the property you linking. Here are some point that you should consider to increase domain authority.

1) When you create a back links, always ensure to have sufficient amount of content. Also, always write fresh content, duplicate content devalue your links. 2) Create back links on website that has higher authority than yours. Suppose your domain authority is 20, in this case create a backlink on website that has more than 20 DA. 3) Do not spam: Do not post anything on spam websites. Instead of getting benefits your website will loose authority.