How do I improve the google pagerank of my site without spending money?

[a2j]

- need practical simple to use tips
- please do mention URLS of sites if you mention them
Added:
- yup I know that free is less quality than paid!
- my first couple of sites has great content and presently have a rank of 4/10 and 3/10 respectively
- my new site is still sitting at 0/10 - it has quality content and an interactive community and quite a lot of visitors (a few 1000 per day), but the PR doesnt budge!

[John J]

To improve page rank you need to improve the content of your site, and increase the number of relavent links.

If you use Apache and have lots of dynamic content and thus large query strings, concider using mod-rewrite - some good information on this can be found here http://www.modrewrite.com/

Google does not accept payment for page rank, and if it is found that you did pay for rank through a site, you may get banned from google listings...