You need to get higher PR backlink to your site. Consider do follow back link is counted to improve PR of website. Create some good back link with same niche and from higher PR sites then it will be improving your site rank. Every SEO expert has different logic of how many numbers of PR back links are needed. Insert unique articles in your website and make it social bookmarking (high PR). It will be improving your website PR.
Another thing, don't concentrate to improve PR, concentrate on getting traffic too. High PR doesn't improve traffic.