Your website structure helps search engines rank your website as reliable and relevant! Consideration into the structure of a website occurs in the early stages of the website design process. It starts with gathering content and gets finalized as the project progresses through the conceptual design phase. (See Website Design Best Practices if you are not familiar with the process). When getting started:
Research your target keywords before deciding on your website structure. A great looking website will not be found unless the proper keywords are used.
Decide what keywords your business will target on the homepage and each other page - Decided what each products/services/categories (depending on the structure you decided) effects your on-page SEO ranking
Website Structure
Website structures are either simple or complex and be sequential, hierarchical, or webs
Website structure requires business insight and can be strategic
Website structure must be a strategic process and should never be decided on by solely a website designer
A team member with SEO experience can provide valuable insight to enhance traffic
How A Hierarchical Structure Helps
Helps search engines find all your pages better by indexing
Makes it easier to your visitor to find what he or she is looking for (usability)
Links through all your pages
Number of Levels in Website Structure
A flatter structure makes it easier to find important content
The exact number of levels is project specific, but the rule of thumb is 2-4 levels
A deeper structure may be required and has its purpose but search engines are less likely to index pages too many clicks away from the homepage