What Are Some Black Hat SEO Tactics?
Keyword stuffing
Keyword stuffing (also known by Google as irrelevant keywords) is the practice of overloading keywords into content to increase the frequency of the targeted keyword mentioned and increase the ability to rank.
Examples of keyword stuffing include unnaturally inserting a targeted keyword into content and metadata, and listing cities and states to gain local SEO relevancy.

An easy way to avoid this is to simply focus on creating quality content. Quality content will naturally avoid keyword stuffing, and remove the ability to use black hat SEO tactics.
Cloaking
Cloaking occurs when one redirect with certain content is shown to the crawlers and Google via HTML, while other content is being served with Flash to the user. Another form of cloaking is the creation of a page or content that is only shown to the crawlers and not intended for the user.
An easy way to avoid this black hat tactic is to always create content for users and always utilize HTML. HTML and HTML5 are what Google can easily read and utilize, and it is what both the user and crawlers can see. By providing a good user experience for users and crawlability for the crawlers, this black hat SEO tactic will never be a worry.
Sneaky Redirects
Sneaky redirects are redirects that send a visitor of the site to a different URL than the search engines when they are crawling your site. This can occur when a website uses Javascript to redirect and show content to the user that a search engine is unable to see.
Similar to cloaking, sneaky redirects can be avoided by using HTML5 and providing a good user experience to users and crawlers.

Low-Quality Content
Low-quality content has become more and more harmful to websites since the Google Panda Update. According to this update, sites with poor quality content are unable to work their way to the top of Google searches.
An easy way to avoid this black hat tactic is to avoid keyword stuffing and create high-quality and relevant content.
Paid Links & Link Farms
Paid links are backlinks that you purchase from another website in order to pass PageRank. Buying and selling links include exchanges of money, goods, services, products, etc. for links.
Link farms are websites created to link to a target page or set of pages in an attempt to grow the link value of that website.
Together, paid links and link farms are considered being link schemes that can negatively affect your website’s ranking.
Comment Spam
Comment Spam, also known as user-generated spam, is content created by users or bots in an attempt to generate more traffic or links back to a certain webpage or website. This can include spammy accounts on free hosts, spammy posts on threads, and comment spam on blogs.
An easy way to avoid this is to not participate in it. Comment spam can negatively affect your website’s ranking ability and manual actions may be taken against your website.