As with the rest of life, step one is Don't Panic. The rest of the solution depends on where you are and what help you have.
Jumper Cables: Way back when I talked about my Car Survival Kit, I mentioned carrying a good set of jumper cables in my truck. They are the most basic way to jump start a dead vehicle, assuming you have another car around to jump yours.
Be very careful to not touch the ends of the cables together while they're connected to any battery or car. They can cause a deadly electric shock.
- There are two schools of thought with regard to positioning of jumper cables on the dead car side. Some folks advocate attaching the black lead to a bare metal body piece on the car. I, and various others, feel better results are obtained by hooking the black lead to the negative (marked -) terminal. Either one should work.
- Next, connect the red/orange/light-colored lead to the positive (marked +) terminal of the battery.
- Connect the same colored leads to the same marked terminals on the live car.
- Start the engine on the live car, and allow it to run for a few minutes to give a bit of charge to the dead battery.
- While the live car is still running and connected, start the dead car.
- Disconnect the cables in the reverse order that you connected them.
Plug-In Chargers: If you're at home, or at least near a power outlet, a battery charger gives quick, sure starts, and doesn't require another vehicle. Simply plug it in to the wall, connect the leads to the battery just like jumper cables, and start your car. If you have time, you can allow the charger to actually charge the battery as well.
Jump Start Packs overcome both of those shortcomings. They are a self-contained battery pack with built-in cables and a charging port. The linked unit also contains a light and an air compressor, for inflating tires that may be a bit low. They aren't cheap, but they're invaluable when your battery goes flat in the middle of nowhere. I owned one for several years, and finally wore it out to the point where the battery would no longer hold a charge. They're expensive, but they're very worth it, the first time they save you in the middle of nowhere.
Keep yourself from getting stranded.