If there is one tool that is an absolute must to keep in your car, it's a set of jumper cables. Jumper cables allow you to get your vehicle started in the event that the battery dies. If you own your own set and can't start your car you can ask someone to give you a jump start to get your car running again. Almost everyone will be faced with this kind of situation at least once in their life.
Jumper cables are insulated lengths of heavy gauge wire which have large spring-loaded alligator clips on either end. The red cable is the "POSITIVE" lead, and the black cable is the "NEGATIVE" lead. If your jumper cables are one colour - the clips themselves will be marked with a + (POSITIVE) or - (NEGATIVE). The positive clamps on each end of the jumper cables should only be attached to the positive terminals of the batteries, and the negative clamps should only be attached to the negative post or grounded area of the engine block.
How to jump start your car
Jumper cables are used to draw power from one battery (in another car) and feed it to the uncharged battery (your car).
With the assistance car running, attach a "POSITIVE" clamp to the positive terminal (+) on the assisting car, and the other end of the "POSITIVE" cable to the positive (+) terminal in your car.
The "NEGATIVE" clamp on the same end should then be attached to the negative terminal (-) of the assisting car . Be very careful at this point as the remaining negative clamp should never come in contact with the positive clamps. The last negative clamp should be attached to a piece of metal on the engine block - not too close to the battery to avoid creating sparks.
Note: Always be sure that clips get a good connection on the terminals. Reposition clip if the first starting attempt is unsuccessful.
Start up the assisting car. Power will flow into your battery. Allow a few minutes for the recharging process and then start your car. If the battery has regained enough power or the power from the second battery is sufficient, the engine should turn over and the alternator should begin charging the battery again. If this doesn't happen on the first attempt, the battery may need more time to build up a charge.
Leaving your car to idle, remove the jumper leads in the reverse order that they were applied, starting with the negative clamp on the engine block necessary.
If the 'dead' battery was not caused by leaving your lights on and draining the power, chances are that you need to replace the battery with a new one.