You don't really need to exagerate the swipe, but the 1 second rule is not a bad one to follow.
Make sure that the way you swipe to enroll is roughly the same as the way you swipe to authenticate. Holding the phone in the same way helps a lot.
Swipe from the base of your finger pad, to the tip of your finger.
Always use a pulling motion. Do not push your finger across the sensor.
You can actually unlock the device whether you pull toward the bottom of the phone from the top, or flip the phone around and pull the other way during the swipe. This can be very useful when the phone is in a dock.
If your finger crosses the sensor at a strong angle, you may not be able to authenticate or enroll. Remember that the finger should be aligned as indicated in the animation.
Enjoy! And remember, this is serious security. It's way beyond the pattern lock or a pin. And yet, it's easier to use than either. How often can you add security and make something easier to use at the same time?