Search engine optimization covers two major areas – On-page and off-page. Off-page optimization can also be covered in search engine marketing.
On page optimization encompasses the page items that would give the search engines the information needed to determine what the page is about. This is were you need to figure out the keyword or phrase that will be targeted for the page. Remember, each page can and should be optimized for different keyword phrases, so don’t try to make your homepage fit every keyword phrase you are trying to rank for.
The major on-page items are meta-tags such as title and description and content tags such as headers (h1,h2,..), font options such as strong or bold, keyword placement and density. Important items such as on page anchor text for related pages or sites give the page strength or authority.
Off-page optimization can be everything from proper incoming anchor text and links, articles, press-releases, forum links, directory listings, social media sites, auction sites, and more. These items are not always under your control and are not all equal.