Pay attention as this bit is important:
Google doesn't care about your web site
What Google cares about are individual pages. Each and every single one of them is assessed according to its own individual merits regardless of whether it is a domain's home page or has a URL long enough to tie a knot in.
The implications for the web site designer are significant. All your pages are equally important, making spending lots of time and effort on your home page a waste of money. Google will not list your home page in the search results unless it appropriate. The pages that appear in Google's results for a keyword are there because that page matches that keyword.
As any page on your site could be the first page that a visitor sees, it is best to design all your pages to be welcoming and equipped with money making opportunities. However you will want some pages specifically optimised with content and adverts directly relating to their target keyword.
This is where your major, medium and minor keywords become relevant. (See What Is The Ideal Amount of Keywords for a Web Site? )
Each of your keywords will get it's own landing page. For the major keyword, this should be the home page. For the other keywords it doesn't matter what sort of page it is. If you are using blogging software such as Wordpress or Typepad, each time you post to your blog you create a separate page and any one of these posts can become a landing page for a keyword. Alternatively you may want to create a tailor-made page with it own layout, style and adverts.
The important thing about each landing page is that it contains sticky content that is optimized for the search engines. This will ensure that visitors arriving on it will be interested and not immediately bouncing back to Google looking for a better web site.
Chris Tregenza runs a variety of web sites including MiceLife, writes free seo articles and a SEO Blog
Better search engine placement through article writing.