Find a wire clothes hanger that you will straighten out to create a long wire. A rib from an umbrella will work as well.
You can also buy a tool specifically designed for opening car doors called a Slim Jim, which is a long, thin piece of flexible metal with a hook on the end. Because car thieves often use this tool, however, Slim Jims may not work on some newer cars that have developed ways to protect against their illegal use.
Use a pair of wire cutters to snip off the hook of the hanger on each side of the base of the twisted section below the hook. Cut as close to the base of the twisted section as possible in order to retain as much length in the wire as you can.
Bend the wire to straighten it out as straight as possible. It is very important that the wire is as straight as possible because you will be guiding the wire through the door.
Make a small hook with the end of the wire hanger if you will be opening the inside door handle itself, and a small circle if you will be opening a vertical lock/unlock button. Make sure that the hook is large enough to grasp the handle, and that the circle can just barely fit over the button so that it snags when you pull it up.
Pry open the car door slightly on the side where it meets the door jamb. You can use an inflatable car door wedge, which is a small inflatable bag that safely creates an opening in your car door or window. If you do not have access to an inflatable bag, you can use any sort of rubber material like a door stopper and wedge it between the door and the door jamb. Use rubber to prevent scratching your car’s paint.Make sure to pry under the weather stripping and only pry enough to insert the wire through. Leave the object you inserted in the door jamb as you complete the next step.
Insert your wedge or inflatable bag and either shove the wedge in far enough to create a small crack or inflate your bag. A crack about half an inch wide will be wide enough to thread your wire through.
Insert the wire into the side of the door jamb hook side first if you are trying to open the door handle, or through the top of the window if you are trying to unlock a vertical button. Be careful not to scratch the paint on your car as you complete this step.
If opening the handle itself, direct the wire onto the door handle and grab onto the handle with the hook you bent into the wire. The hook will usually be pointing down and slightly toward the inside of the car in order to achieve the best angle.
If pushing a button or pulling up on a vertical lock, direct the wire from the top of the window toward the button and perform the necessary action. For a button, simply press down with the end of the wire until the doors unlock. For a vertical lock, push the loop you created in the end of your wire down over the lock and pull up until the car unlocks. It is important that the loop is just barely wide enough to slide over the top of the vertical lock so that you can pull it back up.
Open your newly unlocked car door and hit the road!