The main difference between the American Kenpo philosophy and that of other Kenpo styles is that it pays a lot of attention on real life situations which require protection and awareness.
Many traditional Martial Arts styles focus on one target and maximizing power. The American Kenpo philosophy believes that this results in a loss of awareness around oneself. Ed Parker, the founder called this the white-dot-focus where one visualizes a white dot on a black background, which ultimately represents unawareness. By contrast, Kenpoists visualize a black dot on a white background (black-dot-focus), thus allowing their minds to open up with power, protection, and total awareness.
Like many other Martial Arts, the American Kenpo Karate Philosophy includes a creed, written by it's founder Ed Parker. A full guide to this creed can be found here: American Kenpo Karate Creed