I've read raspberry leaf tea from 36w can get the uterus working and make it more effective during labour and helps to make it shorter overall.
Also acupuncture or reflexology from 37w onwards to bring on or encourage labour.
Appreciate any thoughts or experience with the above! This is my first baby and statistically first time mum's are more likely to go overdue or have a longer labour so if there is anything likely to help that would be great!