What is best taxi/bus route from Guangzhou Baiyun Airport to Luoding?

First of all, it won't be easy for you to find a taxi from the airport to Luoding because of the long distance.
Thus, upon landing, you can take the Shuttle Bus Line 1 to Airport Ticket Office of Huanshi Road at first, which costs CNY18/person. Then walk about 650 yards (600 meters) along West Huanshi Road to the Main Passenger Station. Then you can take a direct coach to Luoding at the cost of CNY100/person. The bus schedules are from 07:15 to 23:00 with the frequency of 1-1.5 hours.

In addition, you can buy the tickets when you arrive there.