i don't understand what you are talking about by saying "What are the requirements of Search Engine Optimization?". But for good result, you should use only ethical SEO tactics which includes both on-page and off-page optimization.
You need to start with getting familiar with the concept of improving your organic web ranks over the net, through using a combination of free and paid methods. Links combined with on page elements seem to be among key players over the net today.
It is possible to make a website that would be liked by both people as well as search engines. Contents which are related to the targeted terms and original ones would be adding weight to the domains and through building links, their ranks on search engines would get improved greatly.
Search engine optimization are two - 1. Onpage optimization Meta Tag Preparation Site Analysis Keyword Research & Analysis Web Page/Design Optimization Content Optimization Mod Rewrite / Search Engine Friendly URLs Robots File Creation Competitive Analysis W3C Validation Sitemap Creation &Submission Site Quality Check Link Building Campaigns SEO Recommendation SE Friendly Design SE Friendly Programming SE Friendly Content 2. Off Page Optimization Directory submission Article submission Press Release Submission Forum Submission Social Bookmarking Blog marketing RSS feeds Link Building