For Google, links are still one of the most important ranking factors. A link is equivalent to a recommendation for a website. But a link is not just a link. The quality of the links differs considerably. Bad or manipulated links can even be harmful. Purchased or exchanged links have been reasons for Google to punish websites recently. Many may know the name Penguin: This name stands for certain updates on Google, which have the goal to be able to recognize bad links.
Offsite optimization is used to improve the number and quality of links pointing to your website. There are different ways to do this: Strictly speaking, the only true Google-compliant link building method is the creation of high-quality content. However, asking others for links or promoting them is fine within a certain framework. There are many ways to get additional links. These include articles in social media such as Facebook, Google+ or Twitter. The listing of a website in directories is another link source, but is hardly used today. The quality of the directories should be a priority here.
The best links are those that are in editorial content. It is ideal if a link is set in the text of a topic-relevant contribution. In addition to the position, the link text also plays a role, i.e. which words are linked. Topic-relevant terms can be advantageous, but here too you have to be careful. Because if all links to a website consist only of the target keywords, this seems unnatural for Google. So you'd better make sure it's a healthy mix.
With all these measures, care must be taken not to overshoot the mark and to pursue a slow but steady link building process. If you collect too many links too quickly, you will become suspicious on Google. In addition, one must pay attention to which links are set so as not to become the unintentional victim of a "negative SEO campaign". Negative SEO" is the term used when bad links are placed on a page with the aim of damaging that page.