Sex my dear and lots of it!!!!! There is something in the sperm that triggers labour naturally, that's of course if everything is ready to go. Baby's make their own minds up when they are comming. If not try some spicy food that worked along with the sex with my second. So try these and let me know how you go and good luck :)

Apparently castor oil can induce labour my cousin tried it when she was overdue and she started having contractions within a few hours

Im 37 weeks and im just as eager to get this baby up and moving. Sometimes inductions can be pretty harmful tho. No one knows for sure when the baby is prepared for life outside the womb and the fact that it isnt here yet for you could be some sort of sign. Just give your baby time, as long as its in no distress wait it out a little longer for the health of your new baby :)

Does Castor oil show up on blood work?