more keywords, seo and number of visitors

it depends mainly on visitors and how often your site has been visited, Updated and Ranked. it varies on many ways. a high PR means a higher rank also! :)

Page rank depends on Age of the site and number of visitors on any site.

Page Rank depends website activity like traffic, quality backlink and website status.

It depends heavily on site backlinks and total count of your website pages.

All of these are important to increase Page rank.

its depend on so much factor. but its mostly on content and your backlink.
so increase a backlink . and make quality of content.

Not only a single part will leads to PR, it mainly depends on backlinks, traffic, quality of content and Keywords, so we must focus on each and every part to get best performance.

page rank shows the Web importance if web page and depends of factors like Optimization ,Content ,Navigation ,link building ,Domain Age ,Bounce rate etc...