Consider attaching a loud whistle to your key chain so you can use it if necessary.
Walk only in well-lit areas and avoid short cuts through poorly lit vacant lots and other deserted places.
Walk near the curb on the side of the street facing traffic.
Dress appropriately. If you expect to be walking, wear comfortable and/or visible clothes and shoes you can run in.
If you think you are being followed while walking, change direction and head for a well-lit area with other people around. Cross to the other side of the street rather than confront a male alone in an isolated area.
If you become a victim of an attack, attempt to make as much commotion as possible so that you attract attention. (Scream, blow whistle etc.)
Have a plan in place to deal with a violent situation if it should occur.
Exercise common sense, and be aware of your surroundings, no matter where you are.