|Image courtesy of GM|
When the weather turns cold, your battery is put to the test. The chemical reactions that take place inside of them slow down as the temperature drops, which is why many times people end up stranded when everything is frozen outside.
One great method of prevention is to buy and use a battery charger. Go with one that not only charges quickly, but shuts off once the battery is full. These are essential for vehicles that aren't driven much, but are also useful if you want to ensure even your daily driver's battery will have enough juice to start up the engine every time.
Keep your battery clean, since corrosion and other debris can cause it to not hold a full charge. The area you want to focus on the most is the terminals. Use a wire brush to remove any buildup and spread on a generous amount of dielectric grease to keep the corrosion at bay.
If your car still struggles to start up, have the battery tested by a qualified shop. It might be worn out, or you could have a problem with the alternator, distributor, or other portion of the ignition system. Taking care of the problem proactively is the best route, otherwise you could find yourself sitting in a freezing car as you wait for AAA to show up.