1) Linking to a higher page rank site
Yes, this is difficult but it can be done. If you prove that you are an expert in the same niche and at the same time comes out with different ideas for the same approach. For example, you are blogging on "how to play billard" and you have a trick that has not been featured on that particular high ranking blog, you scored a point.
2) Submit to directories
Submit to directories like Yahoo Directory. This will also create a backlink to your blog. However, some directory do require you to link back to their blog as well so that your blog will be featured higher compared to others. A directory which you must go is Qassia which provide unlimited quality linkback to your blog.
3) Frequent update of your blog with unique content
Interesting content often makes your blog 'sticky'. 'Sticky' in this context means your visitors revisit your blog for more information which they want to know. This will increase the chance that they will link to your blog due to your fantastic content. That is the reason why your content must be unique.
4) Linking to your old articles
Link back to your old articles. This increases the time that visitors will stayed at your blog due to more detailed content. Most importantly, this will increase the chances of your other webpage with PR increase as well. I'm sure you would want your articles to have some PR ranking as well other than your homepage.
5) Adding your article to social networking group
Add your article to places like digg, stumble upon, reddit etc. and you could get linkbacks from them as well. Do not underestimate the power of this social networking group.
6) Participate in forums
This is often neglected by most bloggers because they think it is useless. In fact, if you visit forums of your related niche and actually comment on some of the questions ask by people, you could actually gain some nice reputation over your niche. At the same time, leave your blog link at the signature column which might create some backlinks. Although there are arguements that link on signature are not counted as backlinks but even if it is true, you create some additional traffic for your blog.
7) Have a sitemap
Having a sitemap makes it easier for Google spiders to crawl and index your page. If you have a more organised blog, your page rank will be improved as well.
8) Buying ad links from high PR site
There are some high PR sites who sell links to be placed on their website as backlinks. This is the fastest and easiest way but sooner or later the high PR site will be penalised by Google. However, this doensn't affect you directly because these are inlinks to your site and not reciprocal links. When I say reciprocal links, it means mutal links from 2 blogs. For example, let's look at amos and coco blog. When amos link to coco blog and coco link to amos blog, this is called reciprocal link.
Work on the tips to see your PR grow on the next update. Have fun. Will blog again tomorrow.