Celebrate Success
As a focussed user, I need confirmation, so I know when I'm done.
Overview
Everbody likes positive feedback, especially when they are completing a complex task like a multi-part form.
For web users with austism spectrum disorders achnowledging the end of a process can be very useful, because it makes it really clear that they have finished what they are doing and can move on to something else.
Progress bars
A progress bar is a great way of acknowledging incremental success.