For off page Seo activity Guest Blogging, Forum posting and social bookmarking these are giving more backlinks.
The important to note about off page SEO is that it is used primarily to build links to your website (directly or indirectly). There are many ways to build links to your website and some people have mentioned them, so for example if your had twitter account - you would include your website url inside twitter which links back to your website. This is in essence what off page seo is about. OFF PAGE SEO - Driving link juice from other sites. WARNING - Any link you create directly to your site must be high quality! so NO pr 0 sites and personally for me i stay away from article directories as google tends to frawn on them (except the very high qulity ones).
Off page activities are- Bookmark Classified Article Blog Forum social activities Press Release Podcasting Vodcasting Always use high pr websites and quality content. don,t use low quality websites.
there are free article submission sites on internet, just get registered and start submitting your articles. try this http://www.freearticlesubmission.org/
All the obvious ones help, though many of them have become marginalized over time. Directories are nice...except even on PR6-PR8 directories, your site will be on a PR1-2 page, at best (90% of directory links I see are on PR0 pages, ie they are buried deep in websites). Build a natural link profile, meaning try to include various types of links at a consistent rate. Having some no-follow links won't be bad since that makes it look more natural instead of artificially boosting the link profile with all do-follows (though obviously they will provide more value).
Lots of techniques are in off-page SEO. If you want to boost traffic and rank post daily one content and share on facebook, twitter, g+ and linkedin. Hope this helpful.