Hi Allison,
Here are some suggestions from our site: http://www.myparentingsource.com/learning/topics/potty_training/1038.aspx
Sometimes, kids at this age get excited about big girl/boy underwear. You could go shopping with your child and find his/her favorite character. It's also okay to wait a little longer. It goes more smoothly if your child is also psychologically ready. The key is to do your best to keep it positive as power struggles can prolong the process. This can be hard to do, but keep the goal in mind.
We'd love to hear from some other parents too regarding your experiences.
Best of luck! Please keep us posted.
Coach Nancy