Really Advanced Stuff...

1. Error handling and error messages

2. Form Instructions and Intervening Text

Users tend to enter forms mode then use tab navigation to move through the form. Intervening instructions or questions that apply to multiple inputs are frequently missed causing the forms to be submitted with errors.

• Break 'long' forms into series of pages where the instructions/questions are presented prior to the first form control on each page.
• Warn screen reader users that there intervening instructions in the form. These additional instructions can be placed in the "alt" of an invisible image at the beginning of the form.
• Place the prompt for a group of radio buttons or checkboxes in the LEGEND of the FIELDSET.