Sex worked for my first baby
Do not drink castor oil! All it will do is give you severe cramps and make you sick. Other stuff you can like walking and sex but honestly I was 2 cm dilated with my first for 2 weeks and 4 cm dilated for 4 days...baby will come when they are ready. I know it's hard and I'm feeling really impatient this time with my second but they will be here before you know it! Just let baby do it's thing. :)
Old wives tales say sex, walking, drinking Castor oil. Not sure if any really work though.
You can look up essitial oils called whisper and clary sage those i hear are used by midwives etc to help induce labor.. Otherwise only science proven way that works is nipple stim.