Before embarking on your link building strategy be aware that some of these methods are open to abuse which could have a negative effect or even get your site banned, so please excercise some common sense and only submit your site’s link when it is relevant and reasonable to do so.
So without further ado, here are my 10 tips for obtaining search engine friendly outside links:
1 - Find online forums related to your site and become part of the community (along with a suitable signature that links to your site).
2 - Add comments to blogs with a link to related content on your Website.
3 - Submit on-topic articles to article directories and include your link in the author bio.
4 - Submit your link to the many free online directory sites.
5 - Add your comments to a guestbook and include your url.
6 - Email the webmaster of a related site and ask to trade links.
7 - Offer to provide some content for another site in return for a link back.
http://all-seo-tip.blogspot.com/search/label/Backlinks