Black hat SEO involves techniques such as paying to post links to a website on link farms, stuffing the metadata with nonrelated keywords, and using text that is invisible to readers to attract search engines. These and many other black hat SEO tactics may boost traffic, but search engines frown on the use of such measures. Search engines may punish sites that employ these methods by reducing their page rank or delisting them from search results.
I’d add one thing to number 5: Writing good copy is crucial not just for your Title/snippet, but for your whole page, especially your landing page. You want people to stay on your page for a while and (hopefully) even navigate to other pages you have. Google looks at bounce rate and where they go after they hit your page. Learning to write good copy can not only increase conversion (if you’re selling something) but make your content more impactful and engaging. There are free books at most libraries or online to help.