Actually obtaining links is quite easy if you don’t care much about their authority. But once if you start to have a concern for their authority, your searching strategies will be widened. This authority is nothing but the trust of a site.In bygone days, it was quite easy to know about the authority of a site but in current scenario it is unpredictable. The frequent update of Google algorithm is also a reason for this non stabilization. Hence you are supposed to choose the site which will remain with its standards for ever. But it is not quite easy to point out such sites.
You need to find the site with high user engagement. Always a user engagement site will be SEO friendly site. Since search engines are in favor of users, they rank the site according to the user engagements.There are some sites which get expired soon often. Getting links from such sites will lead to broken links. Once if the site gets expired total effort will be lost. Hence refer to the frequent updates and user engagement to find whether the site in active.
The contents in a site determine its potential to a greater extent. In an authority site all the contents will be uniquely without copying from other sources. All the pages in a site must be relevant to their niche without any deviation. Obviously if all these factors are outstanding in a site, you can determine that the site is authority enough to gain Backlinks for your site. Before approaching such sites, make sure that your site is authority enough to attain links from those sites; because no web master will prefer their site to be spoiled because of inefficient Backlinks.