Vehicle Launch Basics
Find a set of jump leads and make sure they are in good condition.
Locate the batteries both on the dead and on the moving vehicle (usually under the hood, but possibly in the trunk or elsewhere – see your manual.)
Park the ready-to-use vehicle next to the dead vehicle so close that the jumper cables can extend between the batteries of both vehicles Make sure that the ignitions on both vehicles are off
Attach one of the positive (red) terminals of the jumper wire to the positive terminal of the dead battery (marked with a "+" ̵
Attach the other positive terminal to the positive terminal of the good battery
Attach the negative (black) terminal to the negative terminal of the good battery  Replace the black clamp at this end on a piece of unpainted metal under the hood at least 1 foot from the empty one removed battery. (See below: "Save yourself.")
Start the engine of the serviceable vehicle and let it run at 1,500 rpm for at least a few minutes.
After a few minutes, the empty battery should have enough charge to start the inoperable car.
Attempt to start the inoperable vehicle. It should at least turn around. If it does not start after a few cranks, go to step 8. If the vehicle starts, go to step 11.
Remove the cables in the reverse order in which they were placed
Drive the vehicle with the previously discharged battery for about half an hour to charge it before turning off the engine.
Need more information? Here's how to get your car down
So you've cranked your ignition, and instead of your car firing up and taking you to your next destination, it just makes a quick click sound or maybe no sound at all. Looks like you have a dead battery.
If you have some jumper cables in your trunk and another (working) vehicle nearby, you can be back on the road in less than 10 minutes – much less if you bring one of these portable jumpers with you.
Identification of Transition Points
Normally the battery is under the bonnet, but sometimes in the trunk or even under the floor of the passenger compartment. If you open your hood and no battery is found, consult the manual
Once you have found the battery of your car or truck, identify the positive and negative connections. They are the metal posts that protrude from the plastic housing and they will have plus (+) or minus (-) symbols in their vicinity.
Some automakers go the extra mile and the color coordinated battery terminal connection points with red for the positive side and black for the negative side. Once you have identified the positive and negative connections of your battery, do the same for the serviceable vehicle that you use to start your car. Once you've done that, it's time to make connections.
Stay on the safe side
When the vehicle is off, begin the connection process by attaching a red cable clamp to the positive pole of your dead car. As long as part of your jumper cables are connected to a power source, make sure the cable clamps are not touching. This could cause sparking that could increase the risk of fire.
Go to the accessible vehicle and connect the other red terminal to the positive pole of this battery. While you are there, go ahead and attach the black clamp to the negative terminal. Return to the inoperable vehicle and close the circuit by attaching the black clamp on this side to a piece of unpainted metal under the hood, which is more than a foot away from the dead battery.
Do not complete the circuit by attaching the black clip to the negative terminal of the empty battery. That's a recipe for an explosion.
Start Your Engines
Once you have made all four connections to the three terminals and the single ground point, start the engine of the serviceable vehicle and gently press the accelerator pedal to lower the engine speed to about 1,500 RPM to increase. This allows the generator of the moving vehicle to support the charging process.
After the vehicle has been charging the empty battery of the other vehicle for a few minutes, try to start the vehicle with the empty battery. When your dead car starts up again, you may want to shout, "It's alive!" With this theatrical out of the way, you can now begin to disconnect the terminals in the reverse order as you connected them.
If you had to borrow from a stranger jumper cable, thank them generously and let them know that you are on the go car spare to pick up your own set because jumper cables are an absolute essential in your car anytime to have. If this car part load is a few cities even better, a long ride can give your car's alternator sufficient time to charge a battery that just had a near-death experience.