If you can find out what motivates her then give her a reward for going on the potty. With my son it was as simple as getting a piggy bank and he got quarters for going potty, dollars for BM. He liked to carry it around and it really motivated him to go. He did have a few set backs, but it worked out. The not wearing underwear wasn't really successful, but if she likes a certain character you can buy special underwear. We always told him that if he pees on Thomas, or Scooby that they would be very upset. Hope some of this may help you.