Many candidates fail because of their listening comprehension. This is the best article to give advice about improving your listening comprehension. http://aviationenglish.com/learning-advice/resources-to-improve-your-listening-comprehension
There are several types of ICAO English test used for licensing purposes in Hong Kong. Hong Kong Airlines (internal test) ASPEQ (used by Cathay Pacific Airways and Cathay Dragon) Latitude Clear AEROSTAF (used internally at Cathay Pacific Airways) Regardless of the type of test the best way to prepare for an ICAO English test in Hong Kong is with Aviation English Asia Ltd. http://aviationenglish.com/learning-advice/how-to-prepare-for-the-clear--icao-english-test