What is the best way to pace yourself for a marathon walker?

I will be walking in my first marathon soon I 'm worry about how to pace myself so that i can finish strong.|||I have been to many marathons so pace yourself so like u r jogging at the end pull it a notch and acually start running . While everyone will be breath less u will finish strong.|||You should go to chiliving.com it has a great walking and running program...hope it helps