Possibly one of the most widely overlooked aspects of SEO is Site Architecture. Most SEO’s would agree that your URL structure and the keywords used within the URL structure make a significant difference in ranking. If you think about it, a URL structure is just a set of folders or categories. So when you look at setting up your site, start by creating a taxonomy of the keyword groupings you got from your Keyword Research. For example, if your site is about Conditions and Diseases, then your Breast Cancer page should look something like this:
yourdomain.com/diseases/cancer/breast-cancer/
…as opposed to this:
yourdomain.com/di/289?=77/44/index.html
In the first post in this series titled SEO In Context, I mentioned that it is important to help the search engines understand what your site is about, and Information Architecture should be at the top of the list.
Another thing you can do to reinforce the topical relevance within a given section is to create a breadcrumb that links back up the taxonomy. For the example above, the breadcrumb might read as such:
Health > Diseases and Conditions > Cancer > Breast Cancer
These two things should really help to improve the overall structure of your site… and when combined good content and proper keyword research should help to improve rankings.
The only left is a solid linking strategy 
