You must consider article and directory submission. However , I would like to tell you that both on-page and off-page SEO has their own importance. Where on-page is mostly concerned over optimizing the site through SEO friendly codes and meta tags, off-page is all about wide spreading and marketing your site using different methods. If a site's is well Meta tag optimized then search spiders track it soon. Well now after the recent panda and freshness update in Google's algorithm and PR update it's very important to perform quality work to gain importance by search engines especially Google.