Guangzhou Main Station vs the South station

To head for Foshan by subway is the correct choice, but you have to detour a lot by going from the south station to main station. My suggestion is walking to the nearby South Long-distance Bus Station from the South Rail Station to take a direct bus to Foshan. Many buses are scheduled and they may arrive at Hongyun, Gaoming, Dali and Xiqiao Bus Stations of Foshan.