To help improve your page rank you first need to exhange links with high ranked websites, i.e websites that are already high in Google, and their page rank is above 2. Just make sure that the websites you exchange links with is relative to your website, i.e a similar industry, topic, etc.
Try to generate backlinks from relevant high quality sites.....definitely you will get some PR in next PR update.
take backlink relevant to your site having pr and work on it daily basis then check your pr in next update.
Acquire back links from high pr site doing article posting, Comment posting, forum posting and other more activity . Definitely when Google update site pr you will show pr of your site .