The SEO practices that used to work in the past but nowadays are considered unsafe and should be avoided.
Most of the SEO companies are not up to date and using the same 5 practices and this is the reason they are not getting the results they want.
1) Building low quality links
The normal trend SEO companies are following to push a web page higher in the organic search rankings, they simply create a page, add the keywords you want to rank for and build incoming links to those pages
Google has also stated in their quality guidelines that any links intended to manipulate page rank or a site’s ranking in Google search results may be considered part of a link scheme and a violation of Google’s Webmaster Guidelines.