chevy silverado?

First, insert the slim jim in between the door and the window. Next, feel around for the linkage bar that connects the lock to the door handle. Then you jiggle it forward to get it to unlock.

Ford Focus?

You open a coat hanger and tighten the hook to be a little more closed, then you use wood wedges or a flat tool to pry the door open enough to let the hook through into the car. If you want you can use the slim jim to help get the hook past the weather stripping, or you can just save the slim jim to use on a different car that is not slim jim resistant. Pull to get a broad curve in the wire and use it to pull the door handle open. Not easy takes about 20 minutes of steady effort.

camaros

Using a slim jim is too tough, your chances of failure are greater. Use a push rod, (a long metal item to hit power lock buttons, or unlock it manually)Slip it through the passenger/driver window from the top corner of the window just past the door trim.

How to use a slim jim (lock picking)