People have spoken
Article submission(amazines, articlesnatch, goarticles, articleclick etc...), comments, blog (wordpress, blogger etc...), forum activities and social bookmarking (twitter, facebook, stumbleupon, reddit, diggit etc...)
To get good backlinks you need to write quality content in Blog and in article and post it over as many article submission websites you know. Forum participation is also good as well as bookmarking of site content can also be useful for generating quality backlinks.
1. URL Submission
2. Article Submission
3. Forum Posting
4. Blogging and Blog Commenting
5. Keyword Research, Keyword Analysis and Keyword Optimization
6. Basic Data Entry
7. Social Bookmarking and Social Media Marketing
well u do
social bookmarking
directory submission
forum posting
blog posting
blog commenting
article posting
link exchange with high pr sites
search engine submission
Social bookmarking can gain lots of backlinks, You can submit your links in Digg,Stumbleupon and reddit. They have good PR when it comes to bookmarking.
It is not about the activity which may derive the result for you. But how good you optimized the web site and analysis for the quality traffic and result oriented performance.