A big mistake you intentionally make: You abuse your link profile trying to inflate the number of backlinks. Google can take out your pages from its index.
Here are some unintentional mistakes: You are trying to compete with a slow website, especially on mobile devices, that creates bad user experience; you serve pages on insecure HTTP protocol regardless of the Google guidelines to offer HTTPS, so you are missing a slight ranking boost and never make it to the first page; you build your URLs with dynamic parameters that search engines cannot follow and create duplicate content issues; you build a page for each keyword phrase that looks shiny in online research tools.
