Site architecture, in my opinion, is one of the more unusual aspects of technical SEO. I guess it is because this would normally fall under the jurisdiction of a web developer. How this falls into the realm of SEO is when it come to being indexed by Google and other search engines. But good site architecture is beneficial to more than a bunch of bots, it can help your customers navigate your site. Ease of navigation and easily found products will increase conversion rates and decrease abandoned carts, resulting in higher sales.
Step one should be to ensure that you have a sitemap that lists the URLs contained in your website. There are two types of sitemaps, one for people (HTML), and one for robots to crawl (XML). If you just have one, use the one for people, because robots can also crawl that type of sitemap. But, obviously, both are preferable.
Step two is to develop a structure that categorizes your products. Your home page should give your customers a few categories to chose from, to narrow their search down. This category selection should lead to several sub-categories to choose from, which then leads to the list of products. It is important to have a balance of quickly getting to the desired product, without being too general. Lumping all of your products on the same list can frustrate a customer that is looking for a general item, but making that customer search through several pages of unrelated products. Think about the way Amazon.com does it. General categories, that lead to a more specific category, with the option to search.
Step three: site clean-up. If you have a larger website, with a lot of content, you might have crawl errors that need to be fixed. No one wants to have customers landing on 404 errors while navigating their website, that is a sure way to decrease a consumer’s trust. If you just read was utter nonsense to you, don’t worry. This is definitely one of those issues that hiring someone to do it for you is the best option.
This part of technical SEO is important but can wait until bigger issues are fixed. If you have a fast site that is mobile friendly, it might be time to take another look at your site architecture.