Based off of my novel, Fatal Kidnapping, I have researched the subject of what to do in case you think someone is following you.

If you are walking and think someone is following you, suddenly turn the other direction, cross the street, or go into a nearby business.  If you are alone in a park or somewhere secluded, run as fast as you can and do not stop!  Most importantly, scream as loud as you can.  Do not stop screaming.  Keep running until you can find a group of people to run to for help.  Try to put space between you and the attacker.

If someone pulls a gun on you, your best defense is do not go with the person.  Scream and run in a crooked line if possible.  Most attackers will not shoot someone and do not want to bring attention to themselves.

If perhaps, unfortunately, you are grabbed by someone and they stick a gun in your back, try to pry lose and run.  Again, they do not want to bring attention to themselves.  It is better to be shot than to go with them, because if you do, it is likely that they are planning to kill you.

If you cannot break free and you have to get into a car with them, try to drive.  Put on your seat belt, accelerate, and ram the car into a wall.  The person will hit the windshield and then you can escape.

Always remember that the best defense you can use on an attacker, is your elbow.  Your elbow is the strongest part of your body.  Kick them, elbow them, and do not stop punching and kicking.  Your life is at stake, so fight for it.

If someone tries to steal your purse, let them have it.  Throw it away from you, not beside you.  Make them walk to get it.