There are several ways to perform this age old challenge.
One method, from the Grey Matters blog uses an organized system to move around the board in a not too random fashion:
Another, more mentally demanding but impressive demonstration makes use of Peg words that are used in a cyclical fashion:
Finally, if you find yourself needing to perform this feat on stage in front of hundreds of people, this method is going to be the most reliable for large audiences:
Magic Math and Memory 