As I understand it, the Idea is to heat up the pads and burn off oil/grease contaminants leftover from the manufacturing process. However, care must be taken not to overheat the pad and glaze them.
I think you'll get 8 different ways to do this, but here's my strategy:
1: Take the time to get the pads properly adjusted. Park tool's website has a good guide for most brakes
2: I ride around my road for a half hour or so, getting the bike up to 20, then bringing it to a stop. I ride for a bit between to prevent the pads from over heating.
3: Ride. They won't be 100% but they'll be close.