Coding for Accessibility was presented at the HTML5 Meetup in January of 2019.
I started with a Bootstrap template for a medical website. As I customized the template, I had to work through various errors. The template passed automated web accessibility tests because it did have headings as a hierarchy, but the headings were not created logically. Each row of the website was simply the next heading: h1, h2, h3, h4, h5, h6. I changed this to a more logical order
Other concerns are explained in the video: doctype, language, color contrast