Top Ten Web Design Mistakes

of 2005 (Jakob Nielsen's Alertbox)

Cut any questions that are not needed. For example, do you really need a salutation (Mr/Ms/Mrs/Miss/etc.)?
Don't make fields mandatory unless they truly are.
Support autofill to the max by avoiding unusual field labels (just use Name, Address, etc.).
Set the keyboard focus to the first field when the form is displayed. This saves a click.
Allow flexible input of phone numbers, credit card numbers, and the like. It's easy to have the computer eliminate characters like parentheses and extra spaces. This is particularly important for elderly users, who tend to suffer when sites require data entry in unfamiliar formats. Why lose orders because a user prefers to enter a credit card number in nicely chunked, four-digit groups rather than an undifferentiated, error-prone blob of sixteen digits?