I've been to Hongkong twice (2015 and 2017). First trip was when I visited my relatives who are living there and the second was when some of my family/clan decided to travel and visit there.
Two things I can say, famous and tall skyscrapers and such a vibrant country. For theme park adventure, go to Hongkong Disneyland and Ocean Park. Never miss the chance to go to the Victoria Peak through the Peak Tram where you can see the view of the skyscrapers at Victoria Harbour and which you can also enjoy after that. Tsim Sha Tsui is the best place for night and party life. Going to the Po Lin Monastery through Ngong Ping 360 will give you a more cultural vibe of the place. If you want some cheap shopping, go to the crowded and crazy Mongkok Road. Make sure to enjoy Victoria Harbour as well. There are still more places to enjoy specially the food.
This is the Coloring page of Hongkong Illustration for my Wanderlust book that I published in Amazon last February 2017 which I'm revising for a better and bigger version of it. Have fun!