SEO activity can be divided in to two broad categories, namely, offsite SEO and onsite SEO. 

Onsite SEO refers to all the methods used in the design and presentation of your site in order to enhance its appeal to search engines and spiderability.  Onsite SEO includes tweaking hundreds of factors that can increase the quality of information search engines retrieve when visiting your site.  There are no magic formulae for these elements, but using them all appropriately can lead to significant gains in search engine rankings.  Onsite SEO factors include (but are not limited to):

• choice of text within HTML h# tags (for example, <h1> or <h3> tags).  Do not overuse h1 tags, one per page;
• choice of text within HTML title tags.  This should be unique for each page on your site;
• keyword density within HTML body tags.  Historically (and, perhaps, anecdotally), a density of 3% to 5% evenly distributed on pages of over 200 words was thought to be near optimal, although this is near impossible to assess objectively;
• strong relevant internal linking.  Breadcrumb style sub-navigation on pages can strengthen internal linking;
• choice of text within HTML META descr i ption tag.  This should be unique for each page on your site;
• watch out for broken links within your site;
• keywords in HTML <strong> tags;
• use an up-to-date XML sitemap;
• use an up-to-date HTML sitemap;
• place target keywords high up on the page;
• customize 404 pages to include links back to principal areas of your site’s navigation structure;
• use unique and relevant HTML ALT tags on all images;

These are several of the more important factors that influcence onsite SEO, many of which we shall return to in more depth in ensuing articles on this blog.

Offsite SEO refers to the methods employed to improve search engine rankings by maximizing the influence of factors outside your site’s home domain.  For example, building strong, relevant inbound links from other domains/sites.  The principal object of offsite SEO is quality link building.  Link building has evolved to become a full and separate discipline within SEO and we will return on more than one occasion to tackle the many aspects of link building in future articles on this blog.

Ordinarily, onsite SEO should be undertaken before proceeding to offsite SEO efforts and are usually quicker and easier to perform.  Offsite SEO efforts are usually divided in to mid- to long-term projects.