I've discovered this myself. Ignore it if you've already known.

To improve pare ranking (PR) on Google, in just a few days. You'll need to have 2 things
1.Good site content
2.Incoming links from sites with high pr.

For the first, you need to DIY. When you build up a website. You may already know the purpose of your site. You may need lots of work to improve its content.

To have imcomming links, just insert the link to your site in your sig, in all forums and community that you're taking part in. Most of sites have Google Ad on it (include this site).

That's all I want to let you know.