Forum posting,blog commenting,article submission and bookmarking are the best method to increase the traffic of their site.

learn SEO. This is only the way you can get high traffic

-SEO
-Adwords Campaign
-Social Campaign
-Email Marketing
-Article Marketing
-Forum and Yahoo Activities
-Reputed Online Directory
- Or buying traffic from SEOclerks.

Try to increase your back links using blog comments and other methods.Search engine optimization is very important to get traffic.
For more information visit:http://www.bloghint.com/

Here are given SEO Off page tips for increase your website traffic.

Forums discussion
video promotion
Share quality content on Social media sites
Social bookmarking
PPT