Google on Backlinking : My understanding

1. Interact and contribute on forums and blogs. Just keep in mind to contribute in a positive way, rather than spamming or soliciting for your site. 
2. Think of issues or problems your users might encounter
3. Publish a short tutorial or a video providing a solution, or a practical tool. 
4. Humor can be another way to gain both great links and get people to talk about your site. With BuzzSumo  and other social media services constantly growing, entertaining content is being shared now more than ever. 
5. Directory entries are often mentioned as another way to promote young sites in the Google index.
6. take a look at similar sites in other markets and identify the elements of those sites that might work well for yours, too. However, it's important not to just copy success stories but to adapt them, so that they provide unique value for your visitors.
7. Offering bookmarking services