2 days HK and 1 day Macau

Well, once upon HK, you cannot miss the Disneyland, Ngong ping 360, Ocean Park, Victoria Peak and Victoria Bay. Here is my advice about your HK trip:
On the first day, you can visit Ngong Ping 360 frist and then go to Disneyland to enjoy yourself.
On the second day, you can go to the Ocean Park first. Then the Victoria Peak and Madame Tussauds on the peak acan be enjoyed. In the afternoon, you can go down the peak to Victoria Bay to view the show.
Then you may start your Macau trip. Since you have only one day, I suggest you go to visit the Senado Square and Ruins of St. Paul's. If time is sufficient, St. Domingo's Church is also a nice destination.