Courtesy of the W3C:
The links in the Quick Tips below mostly go to the techniques documents that provide implementation guidance – including explanations, strategies, and detailed markup examples.
1. Images & animations: Use the alt attribute to describe the function of each visual.
2. Image maps. Use the client-side map and text for hotspots.
3. Multimedia. Provide captioning and transcripts of audio, and descriptions of video.
4. Hypertext links. Use text that makes sense when read out of context. For example, avoid “click here.”
5. Page organization. Use headings, lists, and consistent structure. Use CSS for layout and style where possible.
6. Graphs & charts. Summarize or use the longdesc attribute.
7. Scripts, applets, & plug-ins. Provide alternative content in case active features are inaccessible or unsupported.
8. Frames. Use the noframes element and meaningful titles.
9. Tables. Make line-by-line reading sensible. Summarize.
10. Check your work. Validate. Use tools, checklist, and guidelines at http://www.w3.org/TR/WCAG