The Page Rank Algorithm
Internal Linking
Another factor that plays an important role in the Page Rank of the pages within a site is Internal linking. It is most common that the homepage of a site has the highest PR of the website. The Internal linking (the links that exists among the home page and the other pages of the site) does not help in increasing Page Rank of a web page, but sharing the Page Rank of the site, and the intensity of your keyword strength and theme.
You should follow the points for internal linking in your site.
Be sure that the home page of your website (index.htm page) is linked to all secondary pages within the site.
Be sure that the secondary pages (pages linked to the home page) of your site are link to each other.
The secondary pages should link to the third level pages (pages that link to the secondary pages) within their level.
The third level pages should link to each other within their level.
The third level pages should link back to the secondary pages from where they are linked from.
The links between the third level pages should not be very complicated and heavy.
Links between the inner pages, regardless of their level is necessary.
All the pages should be linked regardless of level, where the text on the page is keyword specific.
If fourth level pages are also present the same linking structure should be followed that has been specified for the second and third level structure.
Link should be created among pages that is relevant to each other.
Only keyword specific link text / anchor text should be used for linking between pages.
Standard HREFs should be used in links for easy search by search engine spiders.
External Linking
The most significant factor in determining Page rank is external linking. External links are the incoming links that send traffic to your site. Attempt to increase Page rank can be made by contacting other websites to provide you a link back. The websites to whom link request are sent should be relevant and on theme (same theme).