Black Hat SEO is normally defined as the practice of using unprincipled techniques to make your search rankings on top.
Automatically generated content:
Some websites are generating content via the Software. This type of content is very harm for website ranking according to Google search guideline. Automatically generated content has a lot of errors like grammar error, meaningless sentences. You should avoid them.
Cloaking term is refers to displaying different content for users and Google bots. Cloaking is breaking Google webmaster guideline. This technique is extremely dangerous for website ranking. You should avoid the cloaking.
This is also high level black hat techniques. The website gets high ranking in Google and if users are open that website has to redirect to another domain within 1-2 second that is called sneaky redirection. This technique is used for misleading the user. This is unsafe for website ranking. You should avoid the sneaky redirection.
Hidden text or links:
This technique is very dangerous for website ranking. In this technique text and link color match with website background color that is called hidden. Most of using these techniques for improving the keyword density and keyword stuffing. You should avoid these techniques to improve website ranking in search engine.
One of the most common techniques that very harmful for your website is content duplication. A duplicate content can decrease your rank in search results. If most of your content is duplicated, there’s a large probability that your website will be punished and lose rankings.
This technique is also dangerous for your website’s rank. By means of keyword stuffing is process of inserting large number of keywords into web page content and meta content for increasing the page’s rank. You should avoid this technique.