The best way to increase the number of backlinks is through article submission, participate in forum discussion and insert your website link their, blog commenting, social bookmarking etc helps to increase our backlinks to much greater extent.
If you want to create High quality backlinks then you can use various Off-Page SEO Techniques. You can generate Backlinks from Article Submission, Web Directory Submission, Social Media Marketing, participating in Forum Discussions, Social Bookmarking, etc... but if you are looking for good ranking with backlinks then you must have to submit Quality Content.
For me high quality backlinks are backlinks with good quality related and unique content so even comments can be high quality content as soon as they are not spammy. If you build the links yourself like articles or web2.0 links you need to ensure you build backlinks to your backlinks to increase there value.
There are many of process by which you can generate Back-links for your website. but there are only some process can generate Quality Back-links for your website.
You can use the following process:
1. Link Building
2. Forum posting
3. Article posting
4. Blog posting
5. Press release
6. Yahoo Answer
7. Classifieds Ads
8. Image Sharing