When I was waiting for Yasin the midwives said walking was the best thing to get labour going. FIL got a bit over-excited and tried to
take me on a walk around Canada Bay at 1am. It probably wasn't a good idea because my waters broke but I really exhausted which wasn't a good place to be starting labour. So I would recomend walking - but not too much.
They say that chilli and other spicy foods can stimulate your bowel which in turn wakes up your uterus and gets things happening.
Also semen contains whatever is in that gel that they put on people's cervixes to induce labour and an orgasm can make your uterus contract a bit so a bit of sex can help.
Nipple stimulation is supposed to release oxytocin which is what they put in the inducing drip so its can help too.
There are a couple of acupuncture pressure points that stimulate contractions - you could google them or go and see an acupuncturist.

Yasin was a week overdue so by the end of the week I knew almost every possible thing that could bring on labour #-o .

These contractions are helping to get your cervix ready for birth so in a sense you could think of yourself as already being in pre-labour.

Good-luck I hope that things really start happening soon.