Separate Adult Content so the Non-Adult Content Can Rank
If you have a combination of adult and non-adult content, the non-adult content may not be able to rank due to Google’s safe search algorithms. To avoid this, make sure these sections of your site are distinctly separated.
Google Recrawls All URLs Following Major Structural Changes to Understand Context
Google needs to recrawl and reprocess all URLs following major structural changes to understand the new context of these page on the website.
Consider Merging Similar Category Pages to Consolidate Authority in Search
Consider evaluating category pages to see if they can be merged to make even stronger ones, especially if two category pages are ranking for similar clusters of queries.
Content Less Than 3 Clicks From Homepage is Good Practice But Not Required
Keeping content no more than 3 clicks from the homepage is good practice but not a requirement for Google.
Tag Pages Are Usually Seen as Low Quality
Tag pages are usually low quality and look like search results pages, so it doesn’t make sense for Google to show them in search results and the prefer to show pages with content.
Microsites Can Be Seen as Doorway Pages
Microsites often look like a collection of doorway pages. If you are looking to build these microsites up in the long run then this might be an option, but if they don’t have value beyond driving traffic to another site, then microsites aren’t recommended for search and should be noindexed.
Test Navigation Models to Reduce Click Depth & Improve UX
Consider testing out different navigation models on your site to improve user experience and reduce click depth to important products/pages on your site.
Place Links to Important Pages Higher in a Site Hierarchy
Make sure links to your most important pages are relatively high up in a site hierarchy so Googlebot and users can reach them quickly and so Google can pass Pagerank more quickly.
Canonicalise Faceted pages to Non-filtered Version
Google recommends allowing crawling of faceted pages but canonicalise to non-filtered version of that page instead of blocking them with robots.txt.