If you want to improve only pagerank in the Google, then more concentrate on Link-building and Article writing, Google will calculate the Pagerank on many factors like this...But these are the major factors which influence the pagerank.
If you want to increase the ranking of your website then you must have to optimize your website according to the search engines guidelines which can be termed as SEO. While going for SEO you must have to go for quality content and high quality backlinks for your website because in these days the quality matters a lot rather than quantity. So now the ranking factor is quality i.e. quality of backlinks and quality of content.
Ifd you are talking about page rank then relating it with SERP, Page rank matters but has not major influence. In now a days the prime concern on is website is usable, is serving the purpose, how much faster it is, Is it a brand? who are recognizing it(back-link), what is its social presence. These are the major factors, if you have made your website for users, you are working to set up is a brand, it is faster, using ethical ways of Optimization you will be ranked else...
Page rank also depends on damping factor which lies between 0 to 1, usually taken as 0.89, if you are involved in any/some link buy sell activity for gaining page rank you will get penalize. The best way to create quality quantity content which people like to link back.
Last edited by brownagustin; 10-10-2012 at 05:21 AM.
According to my knowledge quality backlinks and content are important for getting High PR. Off page techniques are used for getting Backlinks. I think you have do off page SEO techniques but never be a spammer.
High PR means little if your SERPs are not high. I have PR4 sites that are between page 3 and page 12 while some PR2 sites are on page 1 on most relevant searches. Google will give you a high PR if you have do-follow incoming links from high PR sites whether relevant to your niche or not. SERPs take into account both do-follow and no-follow links from high PR sites but sites from your field count more.