Link building and link baiting is the best way to improve your Pr of an article directory. Increase your link popularity. There are lot of people looking for article directories for their submission.Find out the people and share your site.
Why are you worrying about PageRank so much? It barely means anything anymore. Just carry on doing what you are doing. Don't worry so much about it.
PR increases with the quality of back links and its relevance to your site and also with the flow of traffic. Because PR is the Google's perception of a site's importance. Here are a few on-page optimization techniques to boost your PR ranking. • Directory Submission • Articles Submission (Post Quality content in top article sites with your links for better results) • Press Release Submission • Squidoo Lens Creation • Hub Pages Creation • Social Bookmarking (Digg, Delicious, Stumble, Reddit etc.) • Blog Posting • Be helpful in forums • Social Networking (Facebook, Twitter, Myspace, LinkedIn etc.) (Though you don't get backlinks from social networks, they are some of the best platforms to drive traffic)
link building, try to make it popular among webmasters forums as it may help you to get traffic and some do follow directories may give you backlinks too.
I would suggest to do backlinks from high PR sites. You can also do social bookmarking and forums posting. Blog Commenting is also a good option.
I add every page of my sites to social bookmarking sites. I make about 120-140 bookmarks and that is enough to get PR1 PR2 or sometimes even PR3 for the submitted page. So I get PR not only on my main page but on inner pages also
Get a variety of backlinks from niche related blogs, article sites, paid links, social bookmarking links, etc.
In order to improve your PR, you must learn first how PR was calculated: http://www.webworkshop.net/pagerank.html#how_is_pagerank_calculated
I trust one way linking, go to directory and forum posting. Also consider doing social bookmarking...
I think you have to do backlinks from high PR sites with Do follow links, do directory submission and try to do link exchange.. and make your site popular as well as update your content regular..
One Word for PR Improvement! Only Target to Create Do-Follow Backlinks! it only can give you best results in improvement of your PR