There are two main types of search engine optimization – on-page and off-page. Perhaps on-page is the easier of these two aspects of search engine optimization. It relates to the web page components – the words, and what importance is given to the words on the page.
“What a web page is about” – is the first thing search engines want to know. Search engine robots (or “bots”) do not have the ability to read images or things like java script. So they look at the word elements. They look for various clues within the on the page to find out the important words.
First of all they look for the title of the page (the words within the <title> and </title> tags) as the main clue. Next they look for header tags (<H1> and <H2>, etc.) to see if there are any words between them. They also pay attention to the URL of the page itself (the web page address). As the same word is noticed in the title tags, the header tags and the URL it is easy to guess what the page is about.
At that time they also check to see whether the same words are contained in the body text of the page and how often. The different combination of these words and their frequency on the page, will determine firstly what the page is about, and secondly how important that page is against all other pages about the same thing (your competing pages).

