Don't do in SEO: Keyword stuffing, hide links, doorway pages, duplicate title for every page, duplicate content etc.
I believe that using unethical SEO techniques, try to keyword stuff your content and having no regard for providing web visitors with good content are really bad for SEO. The faster we realize this the better, as otherwise we would have ruined our brand identity.
Using black hat methods on your money site are bad news. Black hat methods on tier 2 sites can be effective.
Directory submission. Google can considerating some of directory spam. So, stop submiting your site to directory
I agree over stuffing your site with random keywords so the content becomes irrelevant and un readable! I see this mistake made a lot by newbies.
Keyword stuffing, doorway pages, overusing 301 redirects, mass spam links (profiles, comments etc) direct to money site.
Reading jacka$$ posts on here telling others what to do and them not having any idea or clue of what the heck they are talking about. That is absolutely the worst possible SEO you could ever do....lol GC