How to increase your page rank

In my previous post about how to increase your page rank, I just wrote about using dofollow commenting and a little bit of directory submission. My purpose of that post was to write about how to do dofollow commenting to increase your page rank. In retrospect, that should have been the title of that post.
From my experience and questions I have asked other webmasters, you can increase your page rank by
1. Do follow Commenting – You would commenting on do follow blogs. Some blogs require a certain amount of comments before the  blog dofollow the commenter. Anytime, you drop a comment, go back to the blog and make sure your comment is do follow. If not, continue dropping comments till it is do follow.
2. Directory Submission – Submit your site to directories that have a PR. Start submitting your site with the highest PR directories you know of. If you have money, it is better to do paid submission. This shows that the directory owner doesn’t allow spam sites in the directory.
3. Link Exchange – Exchange links with sites that have a higher PR. As in biology, diffusion occurs from a region of concentration to a region of lower concentration. When you exchange with a higher PR site, the site would leak some page rank juice to you. Make sure your link is dofollow on the blog. But don’t too have hopes, the higher PR blog might lose its PR on the next update.
4. Internal Linking – If you link to your other post pages, you can pass some PR juice to the pages.
5. Buy Links – You can buy links from other sites. This is the same as link exchange but instead of you giving a link in return, you are giving cash. Google hates webmaster that buy links. If Google finds out, they would reduce your page rank. If your have a low rank like PR 1, 2 or 3, Google would give you PR 0.
Another tip is if you can get other bloggers to link to you in their post page. There are 2 ways which this can happen. One is by your control and the other is not by your control. The one that is by your control, you can do it by looking for blogs that allow guest post, holding a contest or exchanging articles with other bloggers. The one that is not by your control is by writing quality contents, by being controversial, and by attacking other bloggers.