6 very simple tips to help you make web content that is accessible to people with disabilities. (login required)

1. Headings – format titles and subtitles as headings (H1, H2, H3); not just bigger text
2. Lists – format lists as lists, not just numbered lines or paragraphs
3. Tables – format tables as tables and make sure rows and columns are marked-up
4. Alternative text – provide it for all images
5. Hyperlink labels- explain what lies behind the link

Source: https://webgate.ec.europa.eu/fpfis/wikis/display/WEBRAT/Quick+accessibility+checklist (login required)

Video and audio – provide a transcript

This very basic checklist will make sure your content is accessible to disabled users, particularly those who use screen readers. Screen readers rely on the correct use of <tags> in HTML code to denote elements such as lists, headings, tables, etc. The text is then transformed into speech and can be heard through earphones or speakers. The rich text editor (WYSIWYG) in Drupal will automatically tag most elements of a web page. If you are familiar with HTML, you can add tags in the source code. The formatting tools available in Word and Powerpoint can also be used to tag headings, lists and tables.

Alt text, hyperlinks and transcripts

Alternative text

For images that convey meaning, use alternative text to describe it to visually impaired users. Alternative text needs to briefly describe the image's purpose. Every time you upload images, objects and non-text elements, you will be asked for an alt text description.

• Images of text: alternative text should match the text in the graphic if it’s not already duplicated on the page (unless it is purely for decoration).
• Graphics that add meaning: alternative text should be a brief description of the graphic.
• Decorative/ design images:  images that convey no specific meaning, or are used simply to provide an image for the words next to it on the page, should have an empty or null alt text. Visually impaired users expect that a lack of alternative text means that the image is simply used for decoration and has no information value.
• Graphs and charts: Alternative text for graphs and charts needs a more detailed or long description unless the graph’s information is in the page as text.