I fully agree with "techfired." Earlier I also used to follow the "bankrupt's approach" of commenting on relevant posts on other blogs with a link back to my post. It did help me, but to a very lesser extent. All you need to do to increase PR is to purchase quality links from "like-minded" sites. You may also purchase posts on such sites with 2-3 links back to your site - you get "dofollow" links. In this way, search engines would "like" your site and this would increase your PR. I have followed similar approach for my recent blog on jobs and I was pleasantly surprised! My blog's PR from zero to three within just 4 months!!! I can help you achieve this (of course you need to pay for that ). PM me if interested.
I wanted to know one thing sagargemini, how would google react if I buy text links on other blogs ? I have seen google penalizing websites/blogs for buying and selling links that pass link juice.