PageRank is a Google's system in which Google assigns a number to each web page, this number is out of 10. e.g. the page xyz have page rank of 7/10. Pages on web may have the Google PageRank from 0/10 to 10/10. According to 'Google INC' the PageRank is the measure of importance of a web page and according to them 500 million variables/factors contribute to the calculation of PageRank of a web page. Also it has been the tradition of Google that they disclose very less. Same is the case in Google PageRank, Google have not disclosed that what are those factors which help in calculating the PageRank. But they tell that the key is to have original content and rapid updates of content.
So on base of some information disclosed by Google and the experiments & experiences of some webmasters including me reveal that few factors contribute very much to the PageRank of page in your website. Those few factors and guidelines are as follows