Almost one in five Americans lives with some kind of impairment (2012 Census Bureau Report) and can be seriously impacted by a webpage that does not take accessibility into consideration.
Incorporating accessibility best practices helps improve web usability for all users and can also improve your content's findability in search engines.
When reviewing your web content, you can use the acronym HITS to remember the four most common accessibility problems: hyperlinks, images, tables, and structure.
The clickable text of a link MUST be descriptive. If you can't tell where you will go when you click on a link by looking at the text alone, your link isn't accessible.
"Click here" and "Read more" are two of the biggest culprits and should never be used.
Images require captions. Most web content management systems have fields to enter "alt" text for images. That text should briefly describe the image.
If the image is for decoration purposes only and is not relevant content, it shouldn't be used at all. Extra "eye candy" images can make pages load slower on mobile devices and can be a distracting obstacle for someone who is looking for relevant information.
Table elements on webpages are great tools for sharing data; but the worst tool for layout and positioning. They should never be used to align text and images for visual layout purposes.
Tables should include a caption that summarizes the content of the table. Headers describing column or row content should be marked as table header cells (TH) instead of the standard default table data cell (TD).
Web content should be properly structured using heading elements. Headings (H1, H2, H3, H4, H5, and H6) create a navigable table of contents for people using assistive technology.
Most web templates also format headings in such a way that using them also creates a visual hierarchy that helps all users quickly scan and find the content they are looking for. Using headings solely for their visual treatment without taking into account the structural purpose they serve is very bad for accessibility (and findability!) and should be avoided.