Here are some best ways to build backlinks,
* Posting comments on articles and other blogs that are related to your site's topic and content

* Submitting custom articles that you write to article directories

* Submitting your site to directories like DMOZ

Good Luck!

I would like to disagree with you on the article submission point. What's the point of submitting a single article to many directories since Google is going to rank one and discard rest as duplicate.
Guest blogging works for me too. With keyword country as my partner, I am able to find niche related blogs to guest post on.
Few more tips to get going,
-Great content in itself is a natural way of building backlinks
-Proper use of anchor text can enhance the relevance of your target page.
-Share your content on social networking sites and link back to your website
-Submit RSS feed to directories
-Create link baits
-Submit your website to social bookmarking sites and link back to your site
-Participate in forums and communities

We have some ways to build links:
Social Bookmarking
Article submission
Forum Posting
Blog commenting
Blog Submission
Directory submission

hi
think above replies are good enough for your answers thanks to all.

to build backlinks you can do all offpage seo techniques to get backlinks such as directory submission, social bookmarking, forum posting, article submission, blog commenting, blog posting etc. these techniques are the great source of backlinks