The most powerful way to get one-way quality permanent links is link baiting.Link bait is any original and interesting content, which encourage readers to link to. For example, if you think this post is useful and intersting enough, you will probably link to it from your site.

I still can't understand about link baiting !!! would you please describe it more to understand ?

Link baiting is about writing content in a website, which arouses the interest and curiosity of others. It is such a content which other sites love to link because they feel that it should be linked and not because you are asking them to link it. Link bait helps SEO in many ways mainly by link building. Link bait helps to get more links to your website and it increases the chance of your website getting indexed by search engines.