Some will tell you to use casto oil or red raspberry leaf tea, but in both cases, it can cause more damage then help. I highly suggest you stay away from those, or at least talk about it with your doctor before you try it.
Some others will say : eating pineapple, eating spicy foods, long walks, funny movies. And though it’s probably not true, you’ve got nothing to lose (I did eat 2 pineapples the week before going in labor, but not sure if there is a link though!)
The only “proven” way is : SEX… there is something in your partner’s semen that can cause you to dilate.
Good luck and congrats
xxx