Hi Karthik here!
In present scenario, most of the website/blog owners look for multiple ways to increase backlinks to their site, why because, backlinks are considered as a most important factor by search engines in ranking a site. Backlinks are nothing but the number of links that are coming from other sites to a site. Ranking and popularity of a site is calculated only based on its backlinks (incoming links) from other sites. After a long research, I found out some of the ethical ways of getting backlinks to a site and they are discussed here.
1. Exchange Links with other Webmasters: This is one of the simplest methods of getting backlink to a site/blog and this can be done by writing a mail to the webmaster of another site/blog and requesting them to place your link (URL) on their site and in turn, you credit them by placing their link (URL) on your site. This is a win-win approach for both the webmasters. Exchange of links not only increases the backlink but it also has a power to boost the traffic of a site.
2. Submitting your articles to popular Article Directories: The power of Article Directories are known to everyone and submitting your keyword-rich articles to those Directories help you get more one-way backlinks and also more targeted traffic to your site. Article directory submission is most welcomed by all website/blog owners, because it is one of the best ways of getting more one-way backlinks to a site for free. Some of the few popular Article Directories I prefer most is,
1. Go Articles
2. EzineArticles
3. Article Dashboard
4. Article Pool
5. Site-Reference
6. Article Cube
7. Article Alley
8. I snare
9. Articles Factory
10. A1Articles
3. By bookmarking your site: Social Bookmarking sites play a most crucial role in providing more traffic and backlinks to a site. If you prefer to increase backlinks to your site/blog, then it is wise to consider bookmarking your site into “dofollow” social bookmarking sites. Links to your site from “dofollow” social bookmarking sites are taken into account by the search engines while counting backlinks. There are ample numbers of “dofollow” social bookmarking sites available on the net and few of them are listed out here for your reference.
1. Technorati
2. Slashdot
3. Digg
4. Furl
5. Ma.gnolia
6. Dzone
7. Folkd
8. Backflip
9. Reddit
10. De.lirio.us
4. Blog Commenting and Participating in Forum: If you left your blog unnoticed for a while then it’s of no use in making use of it for your business or any other purposes. There come the two simple steps which when used properly without spamming, increase your site’s backlinks to an enormous amount and they are,
Blog commenting: This blog commenting should to be considered as a wonderful tool for getting backlink to a blog from other blogs.
Forum Posting: Forum posting is also considered as a wise technique in getting backlinks and this is done by leaving signature with the blog URL at the end.

I started this blog by Feb 2, 2009 to provide useful and interesting information related to Search Engine Optimization, Search Engine Marketing, Social Media Marketing and Affiliate Marketing. I had and have more interest towards learning SEO and also to blog about it the same. 
Mar 5, 2009 at 23:44:45
Very nice and resourceful article. Thank you very much for sharing.
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Mar 9, 2009 at 22:55:45
Nice Post
Apr 16, 2010 at 13:06:08
A great article written to ethically increase your Google PR. Really helpful.
Oct 26, 2010 at 18:38:07
Very good information Thank’s for your information, i try to implement it to my sites
Jun 30, 2011 at 14:27:37
thanks for the valuable information. this is really very useful to get more backlinks for my blog
Nov 17, 2011 at 14:11:28
grt information,these are the best ways to get more backlinks.really thanks for that data.