I agree most of the guest posts provide do-follow back-links and guest posts are also a great way to drive huge amount of traffic to website or blog. In the past, marketers used to utilize blog commenting to gain back-links but since most of the blogs provide no-follow back-links, marketers and SEO now utilize guest posts in order to boost their rank and product sales as well.
Social Bookmarking Sites, Forum Submission, Blog Directory Submission, Article Submission, Question and Answer, Video Submission, Image Submission, infographic sharing, Document sharing, Local listing and more activities are useful for generate do-follow backlinks
Here are some of the Off page SEO techniques which I am using - 1. Social media marketing 2. Social bookmarking 3. Forum and blog submission 4. Article submisison 5. Image and video submission
I think Web 2.0s are awesome for off page link building. Web 2.0s can help you rank even on competitive keywords and you can optimize your anchor text anytime you want. Just create some web 2.0s and you'll see the difference in rankings within no time. You can also get links from sites like YouTube, Behance, Dailymotion, Quora. Though links from these sites are nofollow still they are very helpful for SEO.