Don't worry about Google Page Rank. It's already been declared dead (http://www.searchenginejournal.com/google-will-probably-updating-toolbar-pagerank-john-mueller-confirms/117691/).
Instead you should figure out how to get high quality and editoral links - which is the essence of page rank.
I would be happy to share with you a lecture I gave on SEO at a business school on SEO, Marketing and Optimization Strategy. Additionally, I would be glad to provide you a set of affordable services that can benefit your site's google page rank.
Google Page Rank should just be one of many signs of a healthy blog/site, but one way to ensure it doesn't drop and possibly even improves over time is to keep the following rules in mind for any content you create:
1) Always provide useful, original, and natural copy on your pages.
2) Keep your "do-follow" links to external sites to an absolute minimum.
3) Use "do-follows" to links within your own site when it makes sense.
4) Keep affiliate links "no-follow"
5) Clean up your posts/pages periodically to eliminate links that are broken, expired, or do not follow Google's preferences.
These are just the basics. There may be other things that are keeping your pagerank below your preferred goal. We can chat more if you're interested! Good luck!