I agree with sparks, have the child see a psychologist. Till then, I wouldn't change any routines. The great thing about seeing the psychologist is as a parent, they will teach you how to be a better parent for your child. That is where the change is going to start.
Like with any child, you have to work on one thing at a time. If you want your child to stop wearing pull-ups, then you will have to just focus on that behavior modification, and not also change routine in other areas.
Most of all, be patient. There will be ups and downs and the mistake I see made the most is resorting to the stick too early. Timeouts are a last resot, try instead to keep them motivated by reminding them about the rewards and do not forget to give them those when they are good. That's basic parenting right there, but that fundamental concept becomes even more crucial with