Start where one sees the signs of a potential rapist. Most of them are eve teasers. Beat the cr@p out of them. Just shout this guy is eve teasing, if many agrees, beat him and then call police.
There was a good campaign started in my city. Operation Garima (Pride). Any person who eve teases or make vulgar calls, harasses a girl, all she has to do is file the report and the guy will be arrested and keep in jail for at least one day. None bailable charges.
It changed a lot. Most guys who eve tease are college going. Any criminal record will ruin their career as a professional in any company. So it delivered good result. A guys once called my fren couple of times, she told me. I know he won't disclose his name or place so I played a trick.
I told him that I will take this number and my FREN to police station and file an FIR. After an FIR, one an report to the mobile company to reveal the owner of the sim and may be the location too. I told him I will get your name and every info and will call your parent to Police stations. He never called again,
It works guys. Hurt where it hurts the most. If you see a guy eve teasing on bike or car, note his bike/car number, take a pic of his from your camera phone and post it on FB.