While doing seo we must focus on lot of point like: 1.Our content must be fresh and unique. 2.Keyword density is also very necessary for seo.
Article posting and directories submission are the one of the effective techniques of one way link promotion.
SEO helps the search engines recognize your relevance to specific keywords that people search for online. The search engine optimization process includes researching keywords, creating content, building links and making sure your website is visible in the search engines.
There are many expert's are different views, but here I say what ever you're doing it's well nut always go with google webmaster guideline.