There aren't any secrets to gaining high PR - it's just a simple case of picking up some high PR links.
I am not an expert, but I believe that if your site can refer to high quality, related website, it can help google determine your "type of content" or "main subject" and make it easier to rank among other websites. I do not know the pagerank algorithm, and I have no clue if it played a role in my site ranking, but I wanted to share all the steps I have done to reach page rank 2 quickly.
All it takes is one or two strong links from high PR pages. I've gotten a brand-new blogspot blog to a PR 4 in under 3 weeks before with just ONE strong backlink.