Like others have said, creating content that people enjoy and want to share is key. There's also a right place/right time environment when it comes to this. Alos, having a natural link exchange is something that many experts recommend. Here's a good summary that I read not too long ago, I think it will help you out
Many sources of backlinks are available; one needs to find which source is relevant for their website. Some of the methods that are available for creating backlinks are forums, question and answer websites, content sharing, guest posting, social bookmarking, Infographic submission and social media posts, etc.
Most of the tactics mentioned like forum posts and Q&A sites will get you low quality links at best.
BTW, speaking of Q&A, Namepros takes a dim view of those who post simplistic questions on various forums and have other accounts make the rounds "answering" them - this will get your account closed.
In the "post penguin" era, Google isn't "penalizing" low quality self-made links (unless they're excessive) - they just ignore them. The best links come from providing value. Quality + outreach will get you the strongest links and they're safe from being penalized or deprecated.
Now SEO is not about building quantity of links. It's about building quality of links. If you still follow the process of creating bulk quantity links, than it can damage your website ranking and traffic.
Build few backlinks from niche sites say 5-10, but these links are more relevant to your site compared to 100 of non relevant backlinks.
Many wellsprings of backlinks are accessible; one needs to discover which source is applicable for their site. A portion of the techniques that are accessible for making backlinks are discussions, question and answer sites, content sharing, visitor posting, social bookmarking, Infographic accommodation and online networking posts, and so on.