your address is usually a single topic, so it’s normal for U.S. forms to ask their U.S. customers for state and ZIP code on the same page. You’d need to have some special reason to justify splitting them. Very short pages seem to be OK if they are clearly about a single topic that is different from the one before and the one after. Don’t feel that pages have to be a minimum length.
Ask anticipated questions before surprising ones. Users generally have ideas about what information they need to divulge. It’s best to ask the anticipated questions before you move into something unexpected or unusual.
Ask less intrusive questions before more intrusive. Ease into questions that may intrude on the user’s privacy by dealing with neutral topics first.
If questions come up more than once, explain the difference between them
Recognizing the amount of work, the form doesn’t have a progress indicator. Instead, it has a summary menu, which it calls “Registration Menu.” As you work through several pages, each like the one shown here, a nice little menu updates itself, and you can click to jump around in the form as you find answers.
Be polite: Assume that your users are trying their best. Don’t use a patronizing or accusing tone. If possible, offer a suggestion about how to correct the error. If the error might be due to a privacy problem, explain why you need the data. If the error might be due to a category problem, explain why you have restricted the categories on offer.