Just do other off page activities like Article posting, Bookmarking, Forums, blog posting...etc. They can help you.
You can get backlinks by adding comments to blogs in your niche, after sometime those links will contribute to increasing your PR but it takes sometime
I am surprised with "other people". You see yourself their page rank. I am sure 90 % link pages are of PR0. If someone denies, don't worry. PR is not of much value. See how many links are available on the page. For example, if you find a PR 2 link-page where you see more than 100 links already added, and at the same time you see a page that has PR0 but only 5-10 are available, just choose second one. That is more beneficial.
If you have a new website with no links then try to save your website bookmarks to a Social media website like Digg or del.ic.ious .You can do Article Submission.Directory submission,Press Releases submission, Forum Signatures, Comment on blogs etc.
Yes surely go for bog comments but use relevant blogs to comment. If your site is related to auto mobile for instance then don't comment on health blogs or you'll be fired.
There are many popular way you cab build back link for any of your website, Directory submission, article submission, forum posting, blog comment, social bookmarking etc
Blog comment and Directory Submit can help you get backlink and traffic as well. With the backlinks, you can increase your PR