After the release of Google Panda & Penguin algorithms its being even harder to build the backlinks. No usual ways like link directories, social bookmarkings, etc... will help in search engine rankings. So i am really curious to know about your latest link building techniques which google should be able to feel as natural.
Learn SEO: http://www.seomoz.org/beginners-guide-to-seo Then you won't need to rely upon useless tactics.. Further reading that will give you a better understanding: http://searchengineland.com/link-building-means-earning-hard-links-not-easy-links-123767 http://searchengineland.com/what-everyone-needs-to-know-about-good-bad-bland-links-129186
Hmmm,! but i realized to make more link building techniques with those current algorithm even i found a precious secret although it is Blog commenting, !
I also suggest blog commenting, but make sure you leave quality comments or your comments won't be accepted by quality sites. And commenting on sites where all the other comments are spam can't possibly have much benefit. I know I get comments every day that have absolutely nothing to do with the post in question, so at the very least: read the post.
Commenting on high pr blogs is very usefull but finding do follow quality blogs related to your niche is a very difficult task so i will say just do commenting on forums and blogs and leave all on GOD and then watch your luck.
.edu and .gov links are especially provides a strong base for your blog and make it able to get rank high in search engine and also a value in the blogosphere. I recommend linking to these domains helps a lot.
I have a blog and i make back link for this by Directory Submission, Forum Posting, Blog Commenting, Exchange Link With Others Relevant Site. I do these by manual process. I think it is good to get a good page rank. I'm satisfied make backlink by these process because i got a good page rank in my blog. Thanks Farabi, Bangladesgh