SEO means Search Engine Optimization.Search engines fix a rank for each website based on the keywords in domain name,content,design of website,TLD,Domain age, number of visitors,loading capacity etc.So to attain a good pagerank will be the aim for all websites/blogs.The Internet users go to a search engine before reaching a web site.When someone types your product or service's key words into a search engine if the site lists in the first page then chances are there that the user might visit the website and become a customer.
You can increase pagerank by good quality articles,regular updates to website,interlinking posts, using keywords/topics that is searched often,social media,affiliate marketing,SEO methods etc.I insist that SEO is the best and steady way to improve a site's page rank.
Service providers like XnYnZ.com provide Search Engine Visibility Service through which they help the user to get the desired pagerank.