Your turn signal is not for your benefit, but for the benefit of other drivers around you. Always signal to show other driver's what you intend to do and do it well ahead of time, not at the last minute. Signal when turning or changing lanes. Turn your signal off when you are done if it doesn't do so automatically.
Do not follow other driver's too closely. The North Carolina Department of Transportation recommends following a minimum of two seconds behind the closest vehicle. Use a landmark and watch the car in front of you pass it, then begin counting. If you reach the mark before you get to "two one-thousand" you are following too closely. Leave more space between you and other cars in inclement weather.
Use your headlights appropriately, not just when it is pitch black. Use them at dusk and dawn and when driving in rain, fog or snow. If your wipers are on, turn on your lights.
A simple tactic for defensive driving is to drive according to the weather conditions. If it is foggy out, turn on your fog or low-beam lights and only drive as fast as you are comfortable with, giving yourself plenty of time to stop if another car, pedestrian or animal comes out in front of you. Use your hazard lights to warn other drivers of potential hazards and if conditions become too inclement, pull over and wait until they ease up.
Learning how to handle your car if you hit slick roads due to ice or hydroplaning due to water will prevent you from hitting another vehicle or obstacle. If you begin to slide, steer the vehicle in the direction of the skid in order to regain control and straighten out the vehicle and turn to the direction you need to go at the end of the skid. If you have anti-lock brakes, apply them as soon as you begin to slide.
Do not focus on other things while driving such as on cell phone conversations, the radio or eating while you are driving. If you need to read directions, pull over. Purchase a hands-free device for your cell phone to prevent distractions while answering or dialing on your phone.