Proven ways to bring on labor

Kelly • Happily married, teaching, and expecting our second July 2018.
I'll be 35 weeks Sunday, but I've been in preterm labor for 3 weeks. I've been given meds and now I'm fine. I prepared myself for him coming...and now the doc said I'm only 2cm and 60%! I'm afraid I'll have to be induced at 40 weeks due to getting so many things to stop labor at 32weeks. What can help bring on labor (that worked for you or someone you know)?