Before even turning on the car, sit down and have a full discussion of the car, how it works, what you want to accomplish and safety (it's not a video game). Then, go to a parking lot in a very safe area and start out with no other cars around. I've found it helpful to have my hand on the emergency break, just in case. If all else fails, there are some great driving schools that you can find in your area to defer to!
Manders has a great answer. My only addition is that you need to be careful that your teen (or you) doesn't feel like they can drive after one or two lessons. Safe driving takes knowledge AND experience. Keep driving with your teen after they have the skills down, so they can get the practice with you in the car.
I would honestly sit down with the driving manual first. Make sure she has read it from front to back. Give her your own quiz, and see how she does. Make sure rules are established before teaching to drive, as well. Show her this video: http://www.youtube.com/watch?v=ztcbfBFeYt8
Teaching to a teenager is most challenging job to a parents. Here are my tips and suggestion make sure she has a learners permit before she start learning behind the wheels. Then send her to a professional driving schools at least two or three sessions. Their are advantage of sending your daughter to the driving school. You need to consider that driving instructors are expert on teaching teenagers. The instructors teaches techniques on how to parallel park, proper changing lanes and more that your daughter and make it easier to remember learn. In addition driving instructors are having big tolerance , they are patient and polite teaching teenager . Thus, make your daughter learn faster.
I seriously think the best way to teach your kids to drive would be to be a fabulous driver yourself. Stay to the right. Use directionals. Don't tailgate. Make a huge deal about putting your cellphone in the glove compartment before you start the car. Don't yell at other drivers (no matter how much you want to!). Kids do what they see, not what they're told. Good luck.