If you suspect that you're being followed, there are a number of steps you can take to help improve your situation.
First, realize that stalking is a predatory behavior. When a predator stalks, they are signifying aggressive intent. They are also constantly assessing the risk and reward of whatever actions they are considering. Everything from the way you walk, the immediate environment, the presence of other people, the presence or absence of police or other authority, and much more are all constantly being evaluated by the predator. Your walk--and your body language in general--can often signify confidence, or a lack thereof, to a predator. Stalking is a means to collect information. It may also be used as a way to improve position through maneuver, or to get you to make a mistake, thus increasing the predator's sense of opportunity. A predator is looking for the greatest gain for the least amount of risk possible.
Second, a predator may have already scouted you or your route, or the area. Repeat offenders often develop favorite methods and places or types of places they prefer to use for stalking and to launch eventual attacks.
Third, fellow self-defense expert Rory Miller states that, predators must develop the distance first. They need to close the distance with you, eventually, in order to attack. But predators will often do so in a way that favors them.
So what can you do? There are a number of things you can do to help improve your situation:
As difficult as it is, try to remain calm. You need to retain as much of your ability to think, to observe, to make decisions, and to take action.
Even as you try to remain calm and keep your wits about you, set your mind to the fact that you may have to fight. Resolve yourself to it immediately, rather than if and when it actually happens. This will help reduce the shock that many people feel when violence is suddenly happening to them. Mentally prepare yourself to fight, if needed.
Moving toward or into a public place. Observe your surroundings and direction of travel, constantly. Are you near any public places? If you're a block away from a Starbucks, for example, try to head to it and go inside. Order something. Watch to see who comes in behind you, or who slows to walk by the store. Take in as much detail to get a description of the person - race, height, distinguishing features like a beard or goatee, clothing. If the person enters the Starbucks behind you, you can quietly tell a worker that you're being followed and feel unsafe and to please call the police, or pretend to take a phone call and do it yourself. If you can't find a store close enough, but there's a large group of people nearby, move toward them.
Whether it's a Starbucks or some other store, or even a store window--find a reason to stop suddenly. Why? So that you can force a reaction in the person following you. Stop and turn and look at a store window. This is also an opportunity to look behind you to see who is following. Get a description. If someone isn't following you, their attention is elsewhere, and your sudden stop shouldn't elicit a response. However, someone following you will often show a reaction when you suddenly stop and turn and look at them. Pretending to take a phone call can also be an option.
Shell game. Enter a crowded building with multiple exits. Move through the crowd and exit through another door. See if the person continues to follow you. Malls, department stores, supermarkets, train stations are good examples of such buildings.
Cross over your route and back again. This works best when you plan your route, if you believe you've been followed before. Plan your route to your destination, scout it ahead of time, looking for areas and points at which you can cross over the route and back again. This forces someone following you to do the same or to break contact or to expose themselves.
Don't assume there's only person involved in following you. A person following behind may be the "eyes" observing you or trying to drive you toward a second person or group. Be aware of vehicles approaching. Predators often work alone. But sometimes they don't.
What about being followed while driving? You can do many of the same maneuvers as with walking, but some maneuvers are unique to vehicles. For example, crossing over your route can be done by making several right or left turns and seeing if the following car stays with you. Entering a public place can be achieved by driving into a busy store parking lot such as a supermarket and then trying to use pedestrian and other vehicle traffic to delay or lose the following vehicle. Another tactic is to put your turn signal on well in advance of an intersection or exit and seeing if the following vehicle does the same, then turning off the turn signal and proceeding straight at the last second. If the following vehicle does the same, it can be an indication of following. Remember, you can also use your phone GPS to find a police station and drive there.
In each of these cases you can also try to take a moment to call police. Use Siri or other voice recognition on your phone to do it if you don't want to hold your phone up to your ear.
Finally, if you find that you must fight, focus yourself and fight to escape. Your objective should be to cause damage as quickly as possible. Eye gouging, palm strikes, elbow strikes, or hammer fist strikes to the nose or mouth--anything you need to do to stop the attack and give yourself a moment to escape is good. Scream and yell to cause attention to be drawn to you and the attacker. A firearm is a great deterrent, but you should always obtain proper training in its possession and use. A knife, Taser, a kubotan, and CS tear gas/pepper sprays are also good (be sure to check your state and local laws to determine what weapons are legal to possess and carry in your jurisdiction). Even a sturdy pen can be an effective improvised weapon.
Self-defense starts with knowledge. We hope this helps.