Black hat SEO is going around search engines terms of conditions to get better ranking. 

White hat SEO is staying within the terms and conditions of the search engine to get better rankings. 

My view is there are so many ways using content marketing, social media, content creation and promotion, keyword rich articles and blogs, keyword rich video and so on ,  why not start there? 

Google has a fabulous resource "Google My Business" that is a good place to start. 

Those are my thoughts, do the housekeeping with respect to SEO first, Have everything in place. If you're not getting up on the search engine rankings that way ( which I would doubt) then try something different. Not before. 

I have to wonder why someone would be looking to understand how to do black hat SEO...

Adrienne is correct, Black Hat SEO is essentially ignoring Google's guidelines with the aim of improving your search performance. It's a practice that was considered more successful years ago but Google is getting better and better at ensuring it doesn't work.

But there are still Black Hat tactics that have shown to work, although I have to preface this by saying that it's going to be temporary and most-likely very short-term. The biggest concern for anyone interested, is what is on the other side of that temporary gain? Because you can't expect you would come back to normal. 

Here are a couple of the areas that I still see work for Black Hat SEOs:
Google My Business. There are still so many spammy GMB listings that rank well. This is why you should expect your Local SEO agency to be helping you fight spam. 
Link Selling & Swapping. Both against Google's guidelines but n the right scenario, both are still working for many SEOs. 
 

Good points Quentin. 

There is so much available to raise the profile that works within guidelines. But some do like to stretch boundaries so interesting advice on ones that work! 

Would love to get your thoughts/experience on this topic @Quentin Aisbett @Adrienne McLean @Rose Davidson @Sonja Ceri @Paul Juchima