If you want your site to rank well in the search engines you need links pointing back to your site, But you don't want just any old links. The best kinds of back links are links that are relevant to your niche . Link building needs to be an ongoing part of your search engine optimization strategy, the more back links you have the better. But don't rush and suddenly get thousands of links pointing to your site, you need to grow your back links naturally.
There are many ways to get back links:
Develop relationships with other webmasters to get reciprocal links from related sites.
Involve yourself in forums related to your niche and include a link to your site as part of your signature file.
Create Squidoo lenses or HubPages with a link back to your site
If you have a blog, add your blog feed to your Squidoo lens or HubPage.
Write articles for article directories and include a link back to your site in the bio box or author's resource box.
Use Social Bookmarking services to bookmark your pages and encourage your visitors to do the same.
Use Twitter to send a 'tweet' when you post a new article.
Create profiles on Facebook, LinkedIn and include links to your site