Section 508 is a federal law that originally set guidelines just for federal websites. However, since it is more attainable than the Website Accessibility Initiative (WAI), which is the A, AA, and AAA ratings.
The WAI is a good standard, but a difficult standard to live up to. It is not just to make a website accessible for all sorts of people with disabilities, but also to old browsers, different browsers, different languages, etc. If it is the Bobby logo you want, aim for A and hope for AA. Even only a few of my pages are AAA approved.
The Section 508 is a more realistic goal. The main thing, if you are doing this for people who are blind, is if the tab button jumps from link to link, it is accessible at the lowest level. BUT, it is how and what order it jumps that can make a difference. It jumps horizontally, which can make table layout tricky.
Some software that I found to be a valuable tool is A-Prompt. It not only evaluates your site, but helps you to fix it. The vast majority of people can’t follow along with what Bobby has to say but there are other evaluation software and sites that are more user friendly.
https://aprompt.snow.utoronto.ca/
https://www.w3.org/WAI/Resources/#er (resources for other evaluation software)
https://www.usdoj.gov/crt/508/508home.html
https://www.section508.gov/
https://www.icanonline.net/sitemap.cfm (scroll way down to Technology>Section 508)
https://www.access-board.gov/indexes/accessindex.htm
https://www.w3.org/WAI/