Personally, the whole selection process isn't hard at all. As much as most people think that being proficient and fluent in English is the main consideration criteria - it is not the case with Cathay. According to my observation, the majority of the candidates do not necessary speak fluent English. I believe that Cathay is interested in the candidates who look pleasant, friendly and customer-orientated. They have over thousands of applicants per quarter, which means competition is fierce. In order to stand out from the group, the candidates need to be fully prepared for the first session - group interviews and presentation. The presentation topics are very straightforward and mostly about developing tourism in Hong Kong. However, candidates would have to place a heavy emphasis on their body language, gestures and eye contact. Generally speaking, candidates who are rather agressive and dominate the discussions are those who get kicked out first. To form a better impression, I would suggest the candidate to smile throughout the interview, (even though it does get tiring and a little bit fake towards the end), maintain eye contact with both the examiner and the candidates as well as addressing your peers with their first name (to show sincerity). And of course, grooming matters. Make sure you wear a suit (not necessary black - be creative, but don't go with sharp colours), tights and heels (of appropriate height: maybe 2-3 inches). Light make up is fine, smokey eyes or dark coloured eye shadows are not preferred. I have also observed that many candidates had their hair tied up into a bun with gel and all that (which resembles the general appearance of a flight attendant), I don't think it matters much, but if you have long hair, tie it up into a ponytail and make sure your fringe does not cover half of your face.
I can only provide details up to the first stage as I was 'kicked out' after the group presentation / interview stage. It was a little bit disappointing as I believe that I am well qualified (if not, overqualified) for the position and did not believe that I performed that badly. I think appearance does matter - I was born with a rather corny face.. and even with light makeup, I still look rather unapproachable and unfriendly. Even though I tried to smile throughout the process, I guess it didn't appear to be natural enough. Also, since my only pair of proper heels broke the day before, I had to go with my 5-inch platform heels. I believe that this is also one of the reasons why I was rejected straightaway.