The first thing you should know is that there are multiple levels of accessibility. See Understanding Web Content Accessbility Guidelines (WCAG).
There are several things you can do right now to increase the accessibility of your website for visitors with disabilities. As a bonus, these things will help with your SEO too.
Your site is compatible with screen reading software that may be used by visually impaired visitors to your site. Review your content and focus on making it concise, yet comprehensive. This screen/browser reading software reads aloud the text content including headlines, paragraphs and text alternatives for visual content like images and videos.
Each of your internal pages already has an H1 heading as the page title. As a general rule, headlines should display in hierarchical order. H2 or any headline less than H2 displays after the H1, and likewise for the other sizes.
The first page in each category (which is typically the overview page) should not display in the menu. Your visitor will arrive at the page when they click the category title.
Be sure to include Alternate Text for every image you display on a page. This way, visually impaired users using screen reading software will be able to understand what is happening in the image utilizing the alt text. Learn more about adding alt tags.
The tag defines an abbreviation or an acronym. Marking up abbreviations is easier than you think, and can give useful information to browsers, translation systems and search engines. Follow these steps in your site manager:
Now, when your website visitor hovers their cursor over the acronym, a title will appear and its text will be sued by screen readers.
Someone who is hearing impaired will be unable to hear the audio on your video. Therefore, it is very important to provide closed captioning or a video transcript so they can follow along with the video. This could be done in the form of a downloadable PDF (be sure to provide a link to a download a PDF viewer). A better solution is to add a text link near the video that links to a page displaying the text of the video transcript.