When to go
Best time
Late afternoon, Sunset
You can find similar conditions any month of the year, but I recommend going from October to April since these months have the best weather.
The Hong Kong skyline is visible throughout most of the day at Sun Yat Sen Memorial Park. I think that late-afternoon and sunset are the best times to go, as the sunset will be prominent from the riverside.
If the weather is cloudy, use this to your advantage and incorporate the clouds, blue sky and foggy skyline in your shot. These elements alongside the Victoria Harbour will complement each other in terms of a balance between urban landscape and nature.
Field tips
Try using a wide angle lens (I used a 35mm), so you can frame the height of the pillars as well as the cityscape in the background.
Position your model in the center of your image to give the photo a symmetrical feel.
The use of leading lines towards the center of the walls helps draw the eye and focuses the attention towards the center of your image, emphasizing the model.
If you're going to stay after sundown, bring a tripod. When the city lights come on you can take some beautiful long exposure shots.