Search Engine Forums, SEO Forum

There are many ways to build natural backlinks for your business. Some of them are pass value to your website some are not.
My favorite methods are:

• Collaborate With Influencers

• Search Q&A Websites like Quora, yahoo answer, etc for Potential Topics

• Article Submission

• Directory Listing

• Guest Posting

• Blog and Forum Comments

• Spy on Competitors

Hope this will help you