Black Hat SEO is the process through which we mainly target the search engine to grab the visitors and increase the revenue instantly. This process don't target visitors, don't care long term investment to earn revenue smoothly and it does not follow rules of search engines. There are several process to do Black Hat SEO for your Website and also presenting the solution of question Why We Should Away with Black Hat SEO as -
Considering all the advantages that SEO has to provide a business, you need to present these advantages and justify the money the customer is paying.
The most tried and true way is to request links.