The easiest way: take taxi to Panyu Hotel which is some 17km away from Lianhuashan Babor in Shiqiao, Panyu. There is the shuttle bus to Guangzhou Airport directly.
Other option: take taxi to Shiqi Subway Station of Line 4 which is 5km away from Lianhuashan Harbor. Then take Line 4 to Shishengwei Station and then change to Line 2 to Haizhu Square or Guangzhou Railway Station. Airport shuttle buses can be found in both of them.