A rule of thumb is always to have a site structure that is 3 to 4 levels deep. What this basically means is that any URL must be reached with only 3 to 4 clicks upon entering your website.
Site structure is one of the most important aspects about any website, search engines need to know which pages are static and which pages are non-static ie. moving and changing. For instance, if you use the Wordpress function of tagging pages you will realise that those pages do not stay the same for long if they are frequently used. Tag pages are mostly moving and changing.
Then there are sections of a site, in Wordpress if the breadcrumb function is used Google assigns these to categories, usually, if they use the term /category/ in the url Google for some reason Google does not always assign categories as sections. The most important aspects of constructing a site structure is making sure that there are sections if there are a lot of categories. Another disaster that frequently happens to Wordpress blogs is that page names often cause duplication errors on webmaster tools.
If there are duplication errors in Webmaster tools then this is most probably how Google sees your website, with errors. The easiest way to fix this problem is to give each page a name in the tab such as “page 1 of the category” or “page 2 of the category”.
Menus are the direction keepers of your website, they guide people into where they want to go. They are also an easy level distinction indicator. Most important linksThe most important links are those that are on your frontpage. If you disagree with this statement then maybe you should consider moving your most important links to your frontpage as this is where they will benefit most.
Categories and Sections:
Sections are parts of a website that basically belong to one topic. If your home page was the starting point of your website then sections would be the starting point on your website for a specific topic. Sections are usually the first level of site structure.
Categorizing content in the correct categories is most important for your content because miscategorization often makes the content fall into the incorrect tier and associates content with irrelevant other content on the individual tag pages.
Tags should be used sparingly, no more than 5 tags per post. The biggest reason for this is because too many tags will once again cause duplication errors, especially if you are concerned about canonicalization. Tags are also good indicators of what part of the content is about. For instance, categories explain the entire topic, whereas tags explain what the topic contains. A category called “car” would explain the topic of an article but not a tag. A tag would rather describe parts of the article referring to things the car is made of or related to.
Sidebar content vs content:
Often we see websites have more sidebar content than the actual content. Search engines, fortunately, know how to prioritize content of what the actual article consists of and leaving the other parts out of the indexed status but often you would search a certain keyword or phrase and land not on the actual page where the search for content is located but rather on another page that has the content you are looking for linked in the sidebar.
The footer should be used for the most important links about your site or for important information. Putting too many links in the footer pointing back to your site and over interlinking could result in a minor penalty downgrading your website on search engine ranking pages.
Never mind Google and search engines. If you have a website with a purpose and you want to achieve something specific your main priority and focus should be user experience. User experience is one of the most important aspects of your website regardless of search engines. User experience can actually be measured, regulated and optimized using tools such as heatmaps and analytics. In analytics, there are many ways to see the engagement people have with your website. This is the basics of any website’s structure or at least should be.