Here are some basic things to look out for:
- Use clear sans-serifed fonts (eg Arial, Helvetica, Verdana)
- Ensure good contrast between text and background
- Check that the text size on the page can be increased (Zoom the page to 200% or try setting Text Size to Largest)
- Make sure that each page has a meaningful title
- Avoid the use of distracting, moving or flashing images
- Use headings, bullets and lists to reduce the density of text and increase white space.
- Left align text
- Avoid the use of frames
- Avoid the use of tables to layout text
- Make sure that the page can be navigated from the keyboard without the use of a mouse.
Could you use it sight free?
- Give each image an alt-tag
- Use descriptive phrases for links not just click here (links should make sense out of context)
- Use different link text if the links go to different places
- Make sure that colour or shape is not used on its own to signal information
- Provide text alternatives/transcripts for essential multimedia clips
The Web Accessibility Initiative (part of W3C) define recognised best practice for accessible websites.