Provide equivalent alternatives to auditory and visual content

Text is considered accessible to almost all people, whilst an image, movie or sound clip may be inaccessible to some people - make sure that the equivalent information is provided as text.

• Add a meaningful ALT tag to an image in HTML:
  <img src = "bluehills.jpg" alt = "photo of hills covered in blue wildflowers">
• Use the LONGDESC tag for an extended description of a chart or diagram.
• Provide the textual script of audio or an equivalent explanation of video.
• If an image map is used for selection, provide a text link as well.

Don't rely on colour alone

Some people cannot differentiate between some colours. Do not, for example, say that all the urgent tasks are indicated in red and other tasks are in blue. Some people will not obtain meaning from this.

Ensure there is sufficient colour contrast between foreground and background - an extreme example is yellow text on a white background, which is very difficult to read.

Pale backgrounds with strong contrasts are best.

Use markup that facilitates pronunciation or interpretation of abbreviated or foreign text

If you use a number of different languages on a page, make sure that any changes in language are clearly identified by using the LANG attribute

E.g. <P>And with a certain <SPAN lang="fr">je ne sais quoi</SPAN>, she entered both the room, and his life, forever. <Q>My name is Natasha,</Q> she said. <Q lang="it">Piacere,</Q> he replied in impeccable Italian, locking the door.<P>

Avoid using abbreviations or acronyms in a document so that it is understandable when machine spoken.  For example, don't use No. for 'number' - it will be read as No not Number.

Ensure that pages are accessible even when newer technologies are not supported or are turned off

• In particular, organise documents so that they may be read without style sheets,
  i.e. text and images generated by the style sheet will not be available to assistive technologies.
• Provide alternative content in case active features (scripts, applets and plug-ins) are inaccessible or unsupported.

Don't use flickering or flashing presentations

Flickering presentations may affect a person with photosensitive epilepsy and they may not be able to turn it off.

Use the clearest and simplest language appropriate for a site's content

Be sure to use meaningful headings and short paragraphs, and avoid jargon etc.

Use tables carefully and appropriately

• Screen reading software reads the information across cells, left to right, top to bottom.
• If you use a table to layout a page, make sure it makes sense in a linear format.
• Make sure line-by-line reading of tables is sensible by identifying row and column headings.
• If using two or more logical levels of row or column headers, take extra care to associate data cells and header cells.

Don't use Frames

Due to their placement on the page, screen reading software has difficulty reading frames.