This is often ignored by many , respected by few and little-acknowledged by majority of bloggers around , this is one fact you must know irrespective of your stance on this pagerank issue google values it and you can't afford to disdain it if you really wanna be a successful blogger.
now do this first go to http://any-tech.ws/page-rank/ to download the pagerank plugin for any browser of your choice then visiting any website with this plugin enabled should display the pagerank without any action from your end.
If your blog is less than 3/10 you seriously need to think twice as how popular & useful your contents is to the vase majority of your users .
To increase your pagerank you need to actually "add link juice" to some of your featured / most read articles by creating a guest post linking directly to this selected articles.
Only summit guest post to blog with at least 3/10 (like [url=obasimvilla.com/blog/category/webmaster/blogging/]my four weeks old blog[/url] ) pagerank as to make your link "worth the stress" .
Make your guest post content rich and informative so as to stay long in the site you are submitting it .
Join forums to increase your pagerank by creating a forum profile with your blog or link to your featured article as the signature (remember to add your blog title to the signature to attract "Link juice" you can start by joining forums like warriors forum , bloggers forum etc
Finally make reasonable contribution to blog that needs one ( maybe a user requesting for help) leaving your link there //always learn not to spam// while doing this more to come in the comments