Be Aware of Other Drivers
You yourself can be a perfect driver with a clean record, but you can't avoid other people on the road that may not be paying as close attention as you. You have to evaluate how other drivers are acting on the road to help anticipate their next move. Always assume that other drivers aren't paying attention and that they may not notice you in the next lane over. Drive defensively by always being aware of the cars around you and try to give yourself an escape route. For instance, if a car in the lane to your right tries to change lanes right into you, make sure the lane to your left is clear so you can move out of the way at a moments notice.
Take Caution in Parking Lots
Always look around you and double check for oncoming traffic multiple times. As you back out of an alley, parking lot or garage, creep out slowly while constantly scanning behind you in both directions. If there is a blind spot where you can't see oncoming cars, you may need to physically get out of your car to check and make sure no one's close by before you inch out further. Keep your eyes peeled for pedestrians and bicyclists as well that might be harder to spot. Again, assume that other drivers don't see you so be sure and wait until the coast is completely clear.
Be Patient at Street Lights
If you're waiting for your light to change green, don't jump out into the intersection right away. You can't assume that other driver's won't run through the red light at the last minute and this is a common way accident's occur. Wait a few moments before proceeding into the intersection. If there is a car waiting in front of you at the light, they may be distracted and not see the light change. Make sure they begin driving before you start moving to avoid rear-ending them.
Always Look Both Ways
It may seem redundant, but this is one of the easiest, yet most important ways you can avoid being involved in an auto accident. Always double check your surroundings before proceeding. Many times, an oncoming driver will change lanes into the lane you're turning in and if you don't double check you could initiate an accident. Parking lots are common scenes for fender-benders. Keep in mind if you're backing out to continue to look in front of you as well. Pedestrians may try and navigate around you walk right in front of your car. Scan around again before pulling forward.
Check Your Blind Spots
Many car accidents could be avoided if the driver checked in his blind spot. This requires you to physically look over your shoulder or out your window instead of just using your mirrors. There are smaller, wide angle mirrors on the market that you can affix to your side-view mirrors. These will help you keep an eye on your blind spots easily. Knowing if people are in your blind spots, and in general just knowing who's around you at all times will help to avoid a potential accident. Also, don't change lanes if there is another car directly two-lanes over. They may be moving into the center lane as well. Again, always anticipating the next move of another driver is key.
Give Other Drivers Space
You never want to be involved in an accident with an 18-wheeler semi-truck. Keep in mind that their sight is very limited due to their length so you must give them proper space. When they turn, they must drastically slow down and take a wide turn that can use up many lanes. Anticipate this if you see their turn signal on. It may look like they're changing lanes when they're really just giving themselves space to make a wide 90 degree turn.